Post Opening Project Evaluation
A2 / A282 Dartford Improvement
and
M25 J1b – 3 Widening
One Year After
September 2010
Notice
This report was produced by Atkins Transport Planning for the Highways Agency for the specific purpose of
the POPE Major Schemes Commission.
This report may not be used by any person other than the Highways Agency without The Highway’s
Agency’s express permission. In any event, Atkins accepts no liability for any costs, liabilities or losses
arising as a result of the use of or reliance upon the contents of this report by any person other than the
Highways Agency.
Document History
JOB NUMBER: 5084038
DOCUMENT REF: A2_A282_M25_J1b3_POPE_OYA_v2.docx
1
Draft
PW
SB
PR
PR
05/2010
2
Revised in response to HA
comments
PW
SR
NDM
PR
09/2010
3
Minor revisions to
Executive summary
PW
4
Minor revision to Executive
summary
PW
Revision
Purpose Description
Originated
11/2010
Checked
Reviewed
Authorised
Date
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Contents
Section
Page
Glossary
iii Executive Summary
vii 1. 2. 3. 4. Introduction
1 Background to Schemes
Other Major Schemes nearby
Scheme Locations
History of the Schemes
A2/A282 Dartford Improvement
M25 J1b – 3 widening
Post Opening Studies
1 2 2 3 4 7 9 Traffic
11 Introduction
Sources of Data
Background Traffic Growth and the Recession effect
Traffic Volumes
Volumes at the junction
Volumes of Traffic on Strategic network
Volumes of Traffic on Local Roads
Traffic flows through the day
Classified Data
Journey Times
Journey Times on A2 main carriageway
Journey Times on M25 main carriageway
Journey times for turning movements at Junction
Traffic Forecasts vs. Outturn
Journey Time Forecasts
11 11 11 14 14 18 22 23 26 27 27 30 32 35 40 Safety
42 Introduction
Data Sources
Accidents
Scope of Accidents Analysis
Forecasts
Security
42 42 43 43 50 53 Economy
55 Introduction
Economic Appraisals
Overall Appraisals Summary with various scenarios
Transport Economic Efficiency
Evaluation of TEE benefits – Summary of Approach
PAR Evaluation of TEE
Monetised Safety benefits
Scheme costs
55 55 56 58 58 59 61 63 5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
i
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5. 6. 7. Benefit Cost Ratio
Route stress/ Journey Time Reliability
Wider Economic Impacts
65 66 68 Environment
71 Introduction
Noise
Local Air Quality
Greenhouse gases
Landscape and Townscape
Cultural Heritage and Archaeology
Biodiversity
Water Quality and Drainage
Physical Fitness
Journey Ambience
71 75 79 81 83 91 95 101 103 105 Accessibility and Integration
108 Introduction
Data Sources
Option Values
Severance
Access to the Transport System
Integration
108 108 108 108 109 110 Conclusions
113 Measurement against NATA Objectives: AST & EST
Measurement against Scheme-specific Objectives
113 113 Appendices
Appendix A Summary of Sources
116 Appendix B Scheme Objectives
118 B.1 B.2 119 120 A2/A282 Dartford Objectives
M25 J1b - 3
Appendix C Environmental Sources
122 C.1 123 Standard list of information required to evaluate the environmental sub-objective
Appendix D
125 D.1 D.2 126 126 Appraisal Summary Table
Evaluation Summary Table
The maps in this document are reproduced from Ordnance Survey material with the permission of Ordnance
Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised
reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways Agency
Licence No. 100018928. Published 2010.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
ii
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Glossary
Accessibility
Accessibility can be defined as ‘ease of reaching’. The accessibility
objective is concerned with increasing the ability with which people in
different locations, and with differing availability of transport, can reach
different types of facility.
ADT, AADT
Average Daily Traffic, Annual Average Daily Traffic. Average of 24 hour
flows, seven days a week.
AIMSUN
A micro-simulation modelling package which simulates movements of
individual vehicles and weaving movements
ALLI
Area of Local Landscape Importance
AM
Denoting the morning peak period. In this study 7:00 – 10:00.
AONB
Area of Outstanding Natural Beauty
AQMA
Air Quality Management Area
AST
Appraisal Summary Table.
This records the impacts of the scheme according to the Government’s five
key objects for transport, as defined in DfT guidance contained on its
Transport Analysis Guidance web pages, WebTAG.
ATC
Automatic Traffic Count, a machine which measures traffic flow at a point
in the road.
AWT, AAWT
Average Weekday Traffic, Annual Average Weekday Traffic. As AADT but
for five days, (Monday to Friday) only.
BCR
Benefit Cost Ratio - this is the ratio of the PVB divided by the PVC.
CO2
Carbon Dioxide
Colourless, tasteless, odourless, non-combustible gas which is present in
vehicle emissions. For transport, this is the main greenhouse gas.
COBA
COst Benefit Analysis
A computer program which compares the costs of providing road schemes
with the benefits derived by road users (in terms of time, vehicle operating
costs and accidents), and expresses the results in terms of a monetary
valuation. The COBA model uses the fixed trip matrix unless it is being
used in Accident-only mode.
CM
Controlled Motorway
Motorway with an automatic speed-control environment, based on MIDAS,
which uses of mandatory variable speed limit signals rather than advisory
speed limits displayed on traditional motorway signals.
Note this is not the same as a Managed Motorway which includes hard
shoulder running in addition to the features of a controlled motorway.
CTRL
Channel Tunnel Rail Link
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
iii
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
DIADEM
Dynamic Integrated Assignment and DEmand Modelling
Variable demand transport modelling software developed for the DfT.
Demand responses are based on: Trip frequency, Time period choice
Mode choice, and Destination choice/distribution.
EAR
Economic Assessment Report
EST
Evaluation Summary Table.
In POPE studies, this is a summary of the evaluations of the TAG
objectives using a similar format to the forecasts in the AST.
GETRAM
Generic Environment for Traffic Analysis and Modelling: A micro-simulation
model computer system used for looking at road traffic behaviour and
patterns in detail.
HA, Highways Agency
An Executive Agency of the Department for Transport, responsible for
operating, maintaining and improving the strategic road network in
England.
HATRIS
Highways Agency Traffic Information System
The Highways Agency (HA) currently maintains, operates and develops
three traffic databases and associated applications. The Traffic Flow Data
System (TRADS) holds information on traffic flows at sites on the network.
The Journey Time Database (JTDB) system holds information on journey
times and traffic flows for links of the network. These two databases are
known collectively as the HA Traffic Information System (HATRIS).
HEMP
Handover Environmental Management Plan
IP
Inter Peak, the time between the AM and PM peaks
Kent Thameside
Kent Thameside is a regeneration area which covers the urban area north
of the A2 in Dartford and Gravesham
KTS
Kent Thameside Model
Owned by Kent CC, the Kent Thameside Model (KTS) is the primary tool
for assessing the transport impacts of expected development around the
Kent Thameside regeneration area. It is a multi-modal transport model,
representing vehicular travel demand.
SATURN software is used for the highways (cars and commercial
vehicles) and the TRIPS software is used to assess public transport (rail,
bus and coach).
Link E
In the original plans for the A2/A282 scheme, at the junction there were a
number of different links which were labelled link A to link G. Link E was a
proposed free-flow link northwest of the roundabout between the A2
westbound and the A282 main carriageway northbound.
MAC
Managing Agent Contractor
Micro-Simulation
Computer software for modelling the effect of different road layouts by
modelling the movements of individual vehicles (cars, buses and lorries)
along the road and through junctions. It is of particular use in assessing
which road layouts will enable traffic to move freely and which would cause
traffic jams.
NAOMI
New Assessment of Motorway Improvements
NAOMI5 was a strategic traffic model developed for the ORBIT multimodal study covering the M25 corridor. Based on Saturn software.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
iv
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
NATA
New Approach To Appraisal
Used for transport scheme appraisal since 1998.
NMU
Non-Motorised User. A generic term covering pedestrians, cyclists and
equestrians
NRTF
National Road Traffic Forecast.
This document defines the forecasts produced by the Department of the
Environment, Transport and the Regions of the growth in the volume of
motor traffic. At the time this scheme was appraised, the most recent one
was NRTF97, i.e. dating from 1997.
NTEM
National Trip End Model
Department for Transport’s projections of growth in travel demand, and the
underlying car ownership and planning data projections.
OPR
Order Publication Report
ORBIT
London Orbital Multi Modal Study (ORBIT) was commissioned by the
Government Office for the South East and made its final report in
November 2002. The intention of the study was to identify causes of
congestion along and approaching the M25, and recommend a preferred
strategy of possible solutions to alleviate the impact of congestion on the
M25.
POPE
Post Opening Project Evaluation
Before & after monitoring of all major highway schemes in England.
PVB
Present Value Benefits
Value of a stream of monetised benefits accruing over the appraisal period
of a scheme expressed in the value of a single present year. For this
scheme, and in current guidance, this is 2002.
PVC
Present Value Cost
As for PVB but for a stream of costs
PM
Evening peak period. In this study 16:00 – 19:00.
QUADRO
QUeues And Delays at Roadworks.
Modelling software which is used to identify the economics impacts of
construction and maintenance
SAM
Scheduled Ancient Monument
SAR
Scheme Assessment Report
SATURN
Simulation and Assignment of Traffic to Urban Road Networks
Computer software for modelling traffic flows on road networks
SCOOT
Split Cycle Offset Optimisation Technique
Dynamic urban traffic control system tool used for managing traffic on
signalised road networks
SNCI
Site of Nature Conservation Interest
SSSI
Site of Special Scientific Interest
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
v
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
TEE
Transport Economic Efficiency
Calculation of transport user benefits based on changes in travel time and
vehicle operating costs.
TEMPRO
Trip End Model Program
Computer software that provides access to the Department for Transport’s
(National Trip End Model NTEM)
Thames Gateway
Thames Gateway is the United Kingdom's largest regeneration area. It
stretches from inner east London both sides of the Thames to North Kent
and South Essex
TRANSYT
Traffic Network StudY Tool
Modelling software developed by the Transport Research Laboratory for
the modelling of road junctions including signalised roundabouts.
TUBA
Transport Users Benefit Analysis.
Modelling software which calculates the costs and benefits that would
accrue to users of a transport system, companies, national and local
government as a result of making improvements to a transport network.
webTAG
Department for Transport’s website for guidance on the conduct of
transport studies at http://www.webtag.org.uk/
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
vi
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Executive Summary
This report presents a study into the impacts of the opening of two Highways Agency Major Schemes:

A2 / A282 Dartford Improvement, opened in December 2007; and

M25 J1b – 3 widening (section 3), opened in July 2008.
These schemes are both located around M25 J2 and their construction periods overlapped hence they are
clearly closely interlinked which is why the Post Opening Project Evaluations have been undertaken in tandem.
A2/A282 Dartford Improvement
Scheme Description
The improvement scheme consisted of the following measures:
Provision of free-flow links for the principal movements at the junction:

-
Viaduct linking A2 westbound to M25/A282 northbound;
-
Viaduct linking M25/A282 southbound to A2 eastbound; and
-
A free-flow slip road for traffic travelling from the A2 westbound onto the M25 southbound;

Widening of the A2 from 3 to 4 lanes in each direction between the M25/A282 and the Bean junction
(1.2 miles), mainly within existing highway boundary with hardshoulders;

Low noise surfacing on widened sections of carriageway and on existing A2 through and west of M25
J2; and

Environmental mitigation measures including noise fences, improved drainage and retaining walls.
Objectives - Scheme Assessment Report / Statement of Case
Objective Achieved?

Reduce journey times and improve reliability;
Yes

Improve safety at the junction;
Yes

Provide enhanced access from the M25 to the major regeneration area of Kent
Thames-side and other regeneration areas in north and East Kent;
Yes

To facilitate access to Ebbsfleet International Rail Station from the national
motorway and trunk road network; and
Yes

Limit the environmental impact, especially noise.
Yes, except where
too early to
conclude
M25 J1b – 3 widening
Scheme Description
The scheme consisted of the following measures:
Widening within existing highway boundary of:

-
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
M25 both carriageways from 3 to 4
lanes from J3 to south facing slips of
J2, and
M25 southbound from 2 to 3 lanes
vii
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
between J1b and J2 and through J2.

Low noise surfacing;

Lighting on the previously unlit section J2 to
J3;

Environmental mitigation measures including
improved water pollution control measures;
and

Infrastructure for a Controlled Motorway on J23 was installed at the same time, although it
was not formally part of this scheme.
Objectives - Scheme Assessment Report / Statement of Case
Objective Achieved?

Reduce journey times by 30-60 seconds;
Y
e
s

Improve reliability;
Y
e
s
T
o
o
e
a
r
l
y
Create jobs in Kent Thames Side
Regeneration Area through increased labour
t
pool and impacts on companies relying on
o
distribution of goods;

c
o
n
c
l
u
d
e
Y
e
s
,

e
Mitigate the environmental impacts and x
upgrade water pollution control measures; c
and
e
p
t
w
h
e
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
viii
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
r
e
t
o
o
e
a
r
l
y
t
o
c
o
n
c
l
u
d
e

Facilitate future demand management
measures to provide some constraint on Y
induced traffic and lock in benefits from e
widening. These measures would be carried s
out separately from this scheme.


Key Findings

One year after opening, these schemes have been successful in achieving almost all their objectives.

The two schemes were constructed at the same time to minimise disruption.

Traffic on this section of M25 has not grown since 2006 and hence flows are now below forecast.
This is linked below expected growth on the M25 in this period, latterly due to the current economic
recession.

Rapid widening techniques within the existing highway boundary were successful for the M25 J1b–3.

Conversely, traffic on the widened A2 has shown higher than expected growth, which may be linked
to the completion of other schemes in the A2 corridor.

Journey times on the widened A2 and M25 have seen journey time savings for traffic in peak periods
in the main direction of flow.

At the junction, there are journey time savings in the peak and inter-peak for most turning
movements. As expected, the highest savings are for traffic now using the new free-flow links with
savings up to 2 minutes for traffic between the A2 westbound and A282 northbound.

Statistically significant safety benefit from the combined effect of the two schemes is much better
than the slight impacts expected.

Infrastructure for a controlled motorway on M25 J2-3 was installed in the period following the
construction of this scheme. At the time of this study, it was not in operation.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
ix
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
x
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Summary of Scheme Impacts
Traffic
Annual Average Daily Traffic on the widened section of the A2 has increased by 7-8% and is now
130,000 AADT. This growth has occurred particularly during the peak periods when journey time savings
are also observed.
44,000 vehicles use the new free-flow links daily rather than needing to use the roundabout.
There has been a reduction of ⅓ in traffic using the circulating carriageway of the roundabout.
Journey Times using the new free-flow links have improved by up to 2 minutes.
Annual Average Daily Traffic on the widened M25 has shown little change and it is much lower than
forecast. This can be linked to the current economic recession.
No clear impact of traffic rerouting from local roads.
Safety
Statistically significant safety benefit from the combined effect of the two schemes is much better than the
slight impact expected. However, this may have been influenced by a change in driver behaviour resulting
from the construction period when traffic cameras were in operation.
CCTV cameras installed are beneficial for security.
Environment
Noise, local air quality and greenhouse gases impacts which are all linked to traffic flows are largely as
expected. Noise barriers are higher hence better than originally planned ones.
Landscape and townscape mitigation in place but OYA is too soon to establish success. Planting has
largely been implemented as expected.
Heritage impacts are largely as expected. Impacts to archaeology are unknown due to limited available
data at this stage.
Biodiversity impacts largely as expected where data is available at this stage. Mitigation by species
translocation took place but there is only limited data on success of these.
Improved water pollution control measures in place but no clear change in water quality has been
measured.
Accessibility
Schemes have improved access to employment and retail for car users.
Schemes provide access to new Ebbsfleet International Station (opened 2007).
Integration
The schemes are consistent with transport strategy policies targeting the Kent Thameside regeneration
area.
Summary of Scheme Economic Performance
Pre Scheme Forecast
Post Opening Reforecast
(2002 Prices)
(2002 Prices)
All prices in 2002 prices,
discounted to 2002 at 3.5%
A2/A282
M25 J1b-3
A2/A282
M25 J1b-3
£179.0m
£207.8m
£169.5m
£161.2m
£0.9m
£2.6m
£14.8m
£22.4m
Total 60 Year Benefits (PVB)
£179.9m
£210.4m
£184.3m
£183.6m
Costs (PVC)
£102.2m
£69.2m
£115.9m
£54.6m
Journey Time Benefit
Safety Benefit
Benefit Cost Ratio (BCR)
2.3
2.2
Economic forecast was based on TUBA models of a wide area including the motorway, trunk roads and
the Kent Thameside area. POPE evaluation is only possible using a simple method based on changes
observed on the key links only. Hence the benefits presented here are likely to underestimates.
Higher than expected accident savings have resulted in much higher monetised safety benefits than
forecast.
Total cost of the two schemes was slightly below the total forecast.
The BCR is almost exactly as forecast and therefore the schemes represent good value for money.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
xi
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
1.
Introduction
Background to Schemes
1.1
Recently there have been two Highway Agency major schemes undertaken around the
intersection between the M25, A2, and A282 in Kent in overlapping time periods. These are:


A2 / A282 Dartford Improvement which opened in December 2007. This scheme involved:

The construction of three free-flow links at the M25 J2; and

The widening of 2km of the A2 east of the junction.
M25 J1b – 3 widening (section 3), which opened in July 2008. This scheme involved:

Widening from three to four lanes of both carriageways between the junctions J2 – 3
and

Widening of the southbound carriageway between junctions J1b – 2, from two lanes
to three lanes.
1.2
These schemes overlap around the M25 J2 and their construction was undertaken in tandem
although they were appraised and funded as two separate schemes.
1.3
Clearly the two schemes have had significant impacts to the road network and surrounding area
and many of these impacts cannot be accurately attributed to one or the other scheme. Hence,
the Post Opening Evaluation (POPE) of these two schemes at the One Year After stage (OYA) is
combined and presented in this single report.
1.4
The location of these schemes in a regional context is shown in Figure 1.1. This highlights the
strategic importance of these schemes.
Figure 1.1 – Regional context
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
1
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Other Major Schemes nearby
1.5
Other major road schemes have been undertaken by the Highways Agency in the area east of the
A2/A282 scheme. These were:

A2 Bean – Cobham widening Phase 1 (Bean to Pepperhill);

A2 Bean – Cobham widening Phase 2 (Pepperhill to Cobham); and

A2/M2 Cobham to J4 widening – east of Phase 2.
Scheme Locations
1.6
The locations of the scheme which are the subject of this report (A2 / A282 Dartford Improvement
and the M25 J1b – 3 widening) and the other major schemes on the A2 listed above, are shown in
Figure 1.2 and the timelines of the schemes in Figure 1.3.
Figure 1.2 – Locations of A2/A282 improvement, M25 J1b – 3 Widening and other Major Schemes
Figure 1.3 – Timelines of Construction Periods of Major Schemes (from west to east)
Scheme
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N D J F MA MJ J A S O N
A2/M2
Cobham
to J4
widening
Ebbsfleet
International Station
opened November
CTRL funded
Phase 1a

Phase
1b
Ebbsfleet jct work
A2 Bean
to
Cobham
Phase 1
CTRL1 opened

A2 Bean
to
Cobham
Phase 2
A2/ A282
Dartford
Improvemen
ts
M25
J1b - 3
Widening
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
2
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
History of the Schemes
1.7
The history and key dates in the time line of the two schemes evaluated in this study are
summarised in Table 1.1.
Table 1.1 – Timelines of schemes
A2/A282 Dartford Improvement
Period
Preferred Route developed by Kent
County Council for DfT
1992
Scheme added to Targeted Programme
of Improvements (now called Major
Schemes)
1998
Reassessment of preferred scheme and
alternatives
2000Oct 2001
Public consultation
Jun-Aug
2002
Draft Orders and ES published
Mar-03
Public Inquiry
Feb-04
Apr-04
Secretary of State’s Decision
One of five M25 rapid widening schemes
added to TPI programme following
recommendations of the ORBIT MultiModal Study
Aug-04
Dec-04
Reassessment of revised scheme with
Link E1 deferred
early-06
Start of construction work
Aug-06
Open for traffic
M25 J1b – 3 widening
Public exhibitions
May-07
Secretary of State’s decision
Jun-07
Construction work began
Dec-07
Aug-08
Widening work was completed and lanes
fully open to traffic
1.8
The timescales of the nearby schemes in the A2 were shown previously in Figure 1.3.
1.9
It should be noted that following the completion of the widening scheme on the M25 which is one
of the subjects of this POPE study, communications and signalling work continued into 2009.
These works were for the Controlled Motorway scheme which at the time of this evaluation was
expected to be introduced later in 2010. The appraisal and evaluation of the Controlled Motorway
scheme are not covered by this report.
1.10
Flows on the M25 were also known to have been affected by the change in the tolling regime of
the Dartford Crossing on 15th November 2008.
1.11
It should be noted that the M25 widening scheme was constructed entirely within the existing
highway boundary and hence the planning stages were simpler than the adjacent A2 / A282
scheme.
1
One of the proposed free-flow links at the junction
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
3
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
1.12
Details of the two schemes are given in the following sub-sections.
A2/A282 Dartford Improvement
Problems
1.13
At the time this scheme was appraised, the key problems were:

Existing M25 J2 and the A2 were both close to capacity;

Incidents on the M25, A2 or Dartford Crossings led to gridlock at the signalised roundabout.

Major developments were planned in North Kent including a new international and domestic
railway station at Ebbsfleet as part of Channel Tunnel Rail Link (CTRL)
Scheme Description
1.14
The scheme included the following measures:


Provision of new free-flow links for the principal movements at M25 J2 / A282:
-
New flyover (E – N) for traffic travelling from A2 westbound to M25/A282;
-
New flyover (N – E) for traffic travelling from M25/A282 southbound to A2 eastbound; and
-
New dedicated slip road (E – S) for traffic travelling from the A2 westbound onto the M25
southbound.
Realignment of the link roads north of the circulating roundabout at J2:
-
From J2 to J1b for access from A2 and M25 northbound into Dartford; and
-
From J1b to J2 for access onto the A2 (eastbound and westbound) and M25 southbound
from Dartford.

Realignment of the entry and exit slip roads from J2 roundabout and A282 north of the
junction; and

Widening of the A2 from 3 to 4 lanes in each direction with hardshoulders, between the
eastern slips for the new flyovers at J2 and Bean junction in the east covering a total of 2km,
primarily within the existing highway boundary.

Environmental mitigation measures including:
-
1.15
Low-noise surfacing on :

the new and widened carriageways;

On the existing A2 carriageway through and west of M25 J2; and

On the A2 through the Bean junction
-
Noise fencing at Hawley Manor;
-
Landscaped earth mounds in many locations 2m high above the carriageway to reduce
noise and provide visual screening;
-
Retaining walls along the widened sections of the A2 to retain the existing highway
boundary, e.g. where the A2 passes through the Darenth Wood Site of Special Scientific
Interest (SSSI);
-
Retaining wall to prevent the proposed east to north link road from encroaching into the
grounds of Hawley Manor;
-
New balancing ponds, for flood prevention, and pollution control measures; and
-
Extensive planting of woodland, shrubs and grassland.
Figure 1.4 illustrates the main features of the scheme.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
4
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 1.4 – Detail of A2 / A282 Dartford Improvement scheme
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
5
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Link E deferral
1.16
In the original A2/A282 scheme proposals, the changed links at the junction were labelled A to G.
As shown in Figure 1.4, the one labelled Link E was to provide a free-flow link for traffic travelling
between the A2 eastbound and A282 northbound, i.e. it was located north-east of the junction.
1.17
At the detailed design stage of the scheme in 2006, a proposal was made for a revised scheme
layout to defer the construction of this link. This revised version offered considerable cost savings
compared to a small loss of benefit and was subsequently adopted into the scheme as-built.
1.18
The revised plan was that this A2/A282 scheme would not include the construction of Link E but
the new layout at the junction would be designed to facilitate the construction of a segregated
free-flow link E at an appropriate future date. The revised plans for the link E part of the design
were:
1.19

Earthworks for Link E associated with the original plan would be carried out as part of the
main works;

A direct link between the roundabout of J2 and the A282 northbound, essentially on the line
of the existing road, would be built; and

Resurfacing of the existing A2 eastbound carriageway and the slip road to J2 from the west
limit of works with low noise surfacing as originally planned.
The deferral option was tested using the junction modelling tool TRANSYT, then with SATURN
and TUBA. These showed that the revised scheme could operate successfully in the opening
year and even with high traffic growth, Link E would not be needed before 2014 or by the design
year of 2022 with low traffic growth.
The Need for the Scheme
1.20
The details of the problems to be addressed by the A2/A282 improvement scheme as
summarised in the appraisals were as follows.
Problems at the Junction
1.21
The junction between the A282/M25 and the A2 is the M25 J2. The then existing junction was a
three level interchange and all turning movement traffic at the junction had to pass through a
signal controlled roundabout at the intermediate (second) level. The problems with that layout
were:

The junction was very heavily trafficked with almost 90,000 vehicles passing through it each
day. With this level of traffic, delays occurred regularly and queues at peak hours often
extended back onto the main carriageways.

Incidents on the M25, A2 or Dartford Crossings lead to gridlock at the signalised roundabout.

The operation of the junction was further complicated by the fact that traffic on the
northbound M25 wishing to exit at J1b had to pass through the J2 roundabout.

Similarly, traffic from J1b wanting to join the southbound M25 also had to navigate the J2
roundabout.

Consequently, conflicts occurred between traffic bound for the Dartford Crossings and local
traffic accessing Dartford via J1b.
Problems on the A2
1.22
At the time of the appraisal, the existing A2 between J2 and Bean Junction carried over 100,000
vehicles per day and was close to capacity.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
6
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Expected issues regarding Future growth

It was expected that in the future, as traffic flows on the roads increased and local
regeneration in the Kent Thameside area of North Kent took place, the existing problems
were expected to deteriorate further.

Much development had already taken place and was planned to take place in future years,
including such major developments as Dartford Park, Eastern Quarry, Northfleet and
Crossways. In addition, the construction of a new international and domestic rail station at
Ebbsfleet between Swanscombe and Northfleet accessed from a new junction on the A2 was
part of the proposals for the Channel Tunnel Rail Link (CTRL).

The scheme was designed to alleviate the existing and anticipated future congestion,
improve safety and contribute towards an integrated and sustainable transport strategy for
the Kent Thameside area. This would be achieved by improving journey time reliability and
by providing better access to local regeneration areas.
Scheme Objectives
1.23
1.24
The objectives of the scheme were specified in the following documents:

Stage 3 Scheme Assessment Report from Order Publication Report (OPR) ;

1998 Roads Review ;

Statement of Case (2004) and

Environmental Statement (2003)
These have been summarised into the following key objectives:

Reduce journey times and improve reliability;

Improve safety at the junction;

Provide enhanced access from the M25 to the major regeneration area of Kent Thames-side
and other regeneration areas in north and east Kent;

To facilitate access to Ebbsfleet International Rail Station from the national motorway and
trunk road network; and

Limit the environmental impact, especially noise.
M25 J1b – 3 widening
The Problem
1.25
As with the A2/A282 scheme, the existing problems on the M25 J1b – 3 were based around
unreliability of journey times.
Scheme Description
1.26
The M25 J1b- 3 scheme was undertaken using rapid widening methods.
1.27
The key principle of rapid widening is that widening should be carried out within the existing
highway boundary, such that no additional land take is required, thus avoiding the need for any
compulsory purchase orders and likelihood of a public inquiry.
1.28
The scheme involved the following:

Widening of :
-
The southbound carriageway of the M25 from two to three lanes between J1b and J2
southbound slip road;
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
7
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
1.29
-
Building the new lanes over the current hard shoulders with new hard shoulders built
alongside, except under or over bridges (all within the current highway boundary).
Low noise road surfacing/fencing to protect properties and reduce traffic noise;

Lighting on the previously unlit section J2 to J3;

New water pollution control measures for surface water runoff within the existing motorway
boundary.
Additionally, during the construction of the scheme, the infrastructure for a Controlled Motorway
was installed along the length of the scheme. This was not part of the widening scheme appraisal
nor was it costed together. Measures included were:
New communications infrastructure including MIDAS, CCTV, emergency telephones, lane
signalling and EMS signing.
It is important to note that Controlled Motorway (CM) was not directly part of this scheme and this
report is based on the period before the Controlled Motorway was operational. The ES stated that
one of the objectives of this scheme was:

1.31
Both carriageways of the M25 from three to four lanes in each direction between the
south facing slip roads of M25 J2 and the north facing M20 link road merge/diverge at J3;


1.30
-
Provision of sufficient communications infrastructure and sign gantries to facilitate the
incorporation of variable speed limits for Controlled Motorway. This would produce more
reliable journey times hence supporting the objective of reducing driver stress.
Figure 1.5 illustrates the main features of the scheme.
Figure 1.5 – Detail of M25 J1b – 3 widening scheme
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
8
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
The Need for the Scheme
1.32
The problems to be addressed by the M25 J1b - 3 scheme, as given in the Appraisal Summary
Table (2006) are:

Unpredictability of travel times;

Lack of orbital routes around London.

Need for access to Thames Gateway regeneration area.
Scheme Objectives
1.33
1.34
1.35
The objectives of the M25 J1b - 3 widening scheme were specified in the following documents:

AST (2006);

Scheme Assessment Report (SAR) ; and

Environment Statement (ES)
These have been summarised into the following key objectives:

Reduce journey times by 30-60 seconds;

Improve reliability;

Create jobs in Kent Thames Side Regeneration Area through increased labour pool and
impacts on companies relying on distribution of goods;

Mitigate the environmental impacts and upgrade water pollution control measures; and

Facilitate future demand management measures to provide some constraint on induced
traffic and lock in benefits from widening. These would be carried out separately from this
scheme and were not detailed at the time of this scheme appraisal although it was planned
than they would be coordinated with this scheme.
Additionally, the M25 scheme was to be packaged with A2/A282 Dartford Improvement in order to
avoid abortive construction work, limit the disruption to road users by completing the two Schemes
within the minimum possible time, and minimise the overall cost.
Post Opening Studies
1.36
This report is the one year after post opening study for these schemes and was undertaken as
part of the Highways Agency’s Post Opening Project Evaluation (POPE) of all major schemes.
POPE of major schemes is undertaken one year and five years after opening.
One Year After study (OYA)
1.37
This POPE one year after study evaluates whether the original objectives of each of the schemes
have been achieved, and provides a comparison of the predicted scheme impacts against those
emerging to date. The overall impacts each of the scheme are also assessed against the
Government’s key objectives for transport of Economy, Safety, Environment, Integration and
Accessibility as defined in the NATA guidance (New Approach to Transport Appraisal).
1.38
More specifically, this report sets out the following:

A comparison of the before and after traffic volumes on the M25, A2, A282 and other key
roads in the surrounding area;

A comparison of before and after journey times on the key routes;

An outline of the changes in accident number on the corridor following the opening of the
schemes;

A monetised comparison of the predicted and actual impacts of the schemes; and
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
9
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Evaluation of the impacts of each scheme upon the environment, accessibility and integration
sub-objectives.
Five Years After study (FYA)
1.39
The POPE five years after study for these schemes will take place in 2013 and cover a similar
scope to this OYA, but allowing for the Controlled Motorway system to be in place and to further
evaluate particularly impacts which are slower to evolve such as wider economic impacts.
Report Format
1.40
The report is set out as follows:

Section 2 – Traffic Analysis. This section is an analysis of the traffic impacts of the scheme
and compares them with the forecast impacts.

Section 3 – Safety. This section discusses whether at this stage, there are emerging
changes in accident patterns as result of the scheme.

Section 4 – Economy. This section examines what economic impacts of the scheme can be
measured and compares these to the forecast benefits.

Section 5 – Environment. A review of the environmental impacts of the scheme is given
and supported by an evaluation of the mitigation measures described within the scheme’s
Environmental Statement;

Section 6 – Accessibility and Integration. A review of how the scheme has affected
accessibility for pedestrians, cyclists and public transport users is presented. Furthermore a
review of how the scheme links with wider policy objectives.

Appendices – data sources used and summary tables
Sources
1.41
The sources upon which this evaluation is based are detailed in Appendix A.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
10
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
2.
Traffic
Introduction
Sources of Data
2.1
The traffic analysis in this section is based on data obtained from a variety of sources representing
the best available data covering the relevant area for the time period covered by this study.
2.2
The data used for both schemes is as follows.
Traffic volumes on Road Network and Turning movements at the M25 J2
2.3
The data sources used are:

Permanent traffic count data from sites on the strategic road network recorded in the HA’s
TRADS database;

Traffic count data from sites on Kent County Council’s roads;

MIDAS data supplied directly by the NTCC to fill the gaps in the data coverage by the TRADS
database;

12 hour turning counts undertaken in 2004 for the purpose of providing base data for the
original consultant’s scheme modelling which were subsequently made available for this
POPE OYA study; and

12 hour counts on the M25 J2 circulating roundabout and selected links undertaken in 2009
for the purpose of this study to compare with the above 12 hours counts and to fill in gaps in
the coverage by permanent sites on the section between J1b and J2.
Journey Times
2.4
2.5
The journey times around this complex junction have been collected using the moving observer
method using GPS technology to collect detailed data on vehicle locations and times for all the
important movements around the junction. Additionally Journey Time DataBase (JTDB) data has
been collected for the journeys on the links. These can be summarised as:

Moving observer surveys from 2004 collected to provide base data for the traffic modelling
work for the A2/A282 scheme;

Moving observer surveys commissioned in 2009 covering the movements around this
junction, the widened sections of M25 and A2; and

HATRIS JTDB on the A2 and M25 for the periods June 2006 and June and September 2009.
All of the moving observer surveys collected detailed GPS data from each vehicle on all the routes
surveyed. This data included recordings of each vehicle’s location at four and one second
intervals for the 2004 and 2009 surveys respectively. Using this detailed data combined with GIS
software has enabled the processing of journey times between selected points to provide
comparative figures for the many possible permutations of movement around the junction even
though the works at the junction for the scheme have changed the alignment of most of the links
and slip roads.
Background Traffic Growth and the Recession effect
Current Economic Climate
2.6
The current economic climate must also be borne in mind throughout this report. According to the
Office of National Statistics:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
11
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
‘Economic growth during the fourth quarter of 2008 contracted by 1.5 per cent. This marks
the second successive quarter of negative growth so, according to the widely-held technical
definition, the UK is now officially in recession. The pace of the downturn appears to be
accelerating and broad-based, with the UK expected to remain in recession throughout
2009’, (Economic & Labour Market Review, Volume 3, No. 2, February 2009).
Wider traffic trends
2.7
Historically in POPE scheme evaluation, the traffic counts from the before period counts have
been factored to take account of background traffic growth so that they are directly comparable
with the counts from the after period. This usually involves the use of National Road Traffic
Forecasts (NRTF) with local adjustments made using Trip End Model Presentation Program
(TEMPRo).
2.8
However, due to the current economic climate which has seen widespread reductions in motor
vehicle travel in the UK as a whole since the latter part of 2008, it is no longer deemed appropriate
to use this method. In order to better understand the traffic growth patterns in recent years, it is
useful to look at the long term trends of traffic in the area and more particularly on the south
eastern part of the M25 where there has been good data availability for the years prior to and
following the scheme opening. The disruption caused by the works for the major schemes
considered in this report and other major schemes on the A2 means that the best data was
obtained from elsewhere on the M25. The three locations on the M25 with reasonable coverage
selected for analysis of the trends were:
2.9

J29 - 30 north of Dartford crossing;

J3 - 4, just south of the widened section; and

J6 – 7, next to M23.
Average Daily Traffic (ADT) flows by direction for the period January 2000 to March 2010 were
obtained from TRADS for each direction. Figure 2.1 shows the profile of this data. Clearly, at
each location there can be a number of local factors impacting on the trend so by showing a
variety of sections, the general trend should be apparent. For the purpose of this study, the key
points from this graph are:

In the early part of the decade, there are clear growth trends on all six sections of the M25;

There is little evidence of any traffic growth occurring in the period following 2006; and

On the sections J3-4 and J29-30 of the M25, there is some evidence of a decline in traffic
flows starting in 2007 or 2008, just prior to the start of the recession.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
12
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 2.1 – Long terms trends in Traffic flows on M25 (ADT by direction)
2.10
Long term traffic data for the A2 has not been included here due to limited availability and more
importantly, the confounding impacts of the other A2 schemes, as shown in Figure 1.2.
2.11
The data on specific motorway locations has also been compared with more generic data
produced by the DfT on estimated traffic flows for all motor vehicles by local authority, region and
for England. This data between 2000 and 2009 is shown in terms of the annual change in the
million vehicle kilometres (mvkm) for Kent (excluding the Medway towns) and the South East
region in Table 2.1.
Table 2.1 – Annual Change in vehicle kilometres on all roads
Year
GB‡
England*
South East*
Kent (excl.
Medway
Towns)*
2000
0.0%
0.0%
0.7%
0.3%
2001
1.6%
1.6%
1.8%
2.3%
2002
2.6%
2.4%
2.1%
2.9%
2003
0.8%
0.7%
0.3%
1.0%
2004
1.7%
1.6%
1.1%
1.4%
2005
0.2%
0.2%
-0.1%
0.0%
2006
1.6%
1.4%
1.1%
0.8%
2007
1.1%
1.0%
1.0%
1.2%
2008
-0.8%
-0.9%
-1.2%
-1.2%
2009
-1.0%
-1.0%
-1.1%
-0.5%
‡
Road Traffic and Congestion in Great Britain: Quarter 2 2010, DfT
*Taken from: Estimated traffic for all motor vehicles by Local Authority: 1993-2009, DfT
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
13
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
2.12
It can be seen that Kent traffic data shows a very similar trend to the South East as a whole, with
annual increases every year from 2000 to 2007, except 2005 when traffic levels were static.
2.13
Vehicle kilometres showed year on year decline in 2008 and in 2009.
2.14
It is considered therefore that some of the reductions in traffic shown later in this section are more
likely to be associated with the impacts of the economic climate than of the schemes.
2.15
Therefore, whilst the impacts of the recession shall be borne in mind, this section of the report
presents the observed unfactored traffic flows at each of the count locations.
2.16
When the scheme was appraised and by the time of the scheme public inquiry (A2/A282) and
exhibitions (M25) in 2004, traffic was still growing as assumed in the traffic forecasting.
Traffic Volumes
Volumes at the junction
Traffic using new free-flow links
2.17
One of the key features of the A2/A282 scheme was the construction of three free-flow links which
are now benefiting traffic making some of the turning movements which previously had to use the
circulatory carriageway of the roundabout. The usage of these links compared with the numbers
previously observed making these movements as average hourly flows and total 12 hour flows are
summarised in Table 2.2.
Table 2.2 – Traffic movements using new free-flow links compared to equivalent movement before
Link
Time
period
2004
2009
Difference
% Diff
AM
800
1,000
200
19%
IP
900
1,000
100
12%
PM
1,100
1,400
300
28%
12H
10,900
12,800
2,000
18%
AM
900
1,400
400
44%
IP
800
1,000
100
17%
PM
400
700
300
71%
12H
9,000
12,000
3,000
33%
AM
700
900
300
38%
IP
600
600
0
5%
PM
700
800
100
18%
12H
7,700
9,000
1,300
17%
AM
2,400
3,300
800
34%
IP
2,300
2,600
300
12%
PM
2,200
2,900
700
33%
12H
27,600
33,900
6,300
23%
(weekday)
A282 SB to A2 EB
(new free-flow flyover)
A2 WB to A282 NB
(new free-flow)
A2 WB to M25 SB
(new free-flow)
Total on links directly
improved by the scheme
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
14
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
2.18
The key points on the traffic volumes on the free-flow links are:

Counts of traffic using the new free-flow links shows that 33,900 vehicles are using these new
free-flow links in the 12 hour period observed. Converted to a 24 hour average day2, this is
44,000.

The 2009 data shows that increases in traffic primarily in the peak periods. This is likely to be
due to the impact on the congested conditions which in the before period caused trip
suppression, rerouting away from the junction and peak period spreading; and

The greatest change can be observed in the traffic making the movement from A2 WB to
A282 NB which benefits from the new flyover (Figure 2.2) which replaces the need to make a
270° turn at the roundabout.
Figure 2.2 – New Flyover (A2 WB – A282 NB) from A2 EB onslip
Circulating traffic
2.19
The construction of the new free-flow links was also intended to improve conditions for other traffic
using the junction making movements which still include using the signal controlled circulating
carriageway. Previously, all turning movements at the junction used the circulating carriageway
except for a single free-flow link between the M25 NB and A2 WB. Following the completion of
the A2/A282 scheme the only important movements which still need to use the roundabout are:

From A2 EB to :
-
A282 NB,
-
J1b via link road for access to Dartford
-
M25 SB

From A282 SB to A2 WB

From J1 b via link road to A2 EB and WB
2
Conversion of 12 hour weekday flow to 24 hour ADT using a factor of 1.3 derived from the average ratio at
nearby locations
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
15
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

2.20
From M25 NB to:
-
A2 EB
-
Link road to J1b for Dartford
Table 2.3 shows the change in the total traffic using the circulating lanes of the roundabout at the
junction. Traffic using the new free-flow links are not included. The traffic using the roundabout
would be expected to benefit from the reduction in circulating traffic.
Table 2.3 – Circulating Traffic at Roundabout – not using new free-flow links
Time Period
2004
2009
Difference
% Diff.
AM peak hourly
5,600
3,600
-2,000
-35%
Inter Peak hourly
4,900
3,100
-1,900
-38%
PM peak hourly
6,300
4,300
-2,000
-32%
12 hour weekday total
65,400
42,200
-23,200
24 hour AADT*
85,000
55,000
-30,000
-35%
*Estimated using ratio as 2.18 above
2.21
This clearly shows that:

Traffic circulation on the roundabout has reduced by around a third;

The reductions are fairly consistent throughout the day; and

The traffic volume using the circulating lanes is now 55,000 AADT compared to 85,000
before the new free-flows were added.
Traffic using links at roundabout
2.22
A more detailed breakdown of where the changes have occurred at the roundabout is shown in
Table 2.4. It should be noted that this data is based on single day video surveys in both 2004 and
2009 and hence may not precisely reflect the pattern over a longer period.
2.23
The main points are:

The greatest change has occurred east of the roundabout where the construction of the two
new flyovers between the A2 and the A282 and the free-flow slip road to the M25 southbound
has resulted in significant drops in the traffic directly accessing the roundabout. Most notable
is that from the A2 westbound, traffic using the roundabout circulating carriageway is down by
87%;

South of the junction, the new free-flow slip has reduced the traffic travelling from the
roundabout to the M25 southbound by 45%; and

North of the junction the new flyover has reduced traffic approaching the roundabout from the
north by 33%.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
16
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Position
from RBT
Table 2.4 – On and off slips to and from the roundabout
E
2004
Slip movement
(RBT=roundabout)
2009
AM
IP
PM
12 hour
AM
IP
PM
12 hour
AM
IP
PM
12 hour
RBT to A2 EB onslip
1,500
1,600
2,300
21,300
800
1,000
1,200
12,400
-47%
-38%
-48%
-42%
A2 WB offslip to RBT (inc.
new free-flow slip to M25)
1,800
1,600
1,600
19,600
1,200
800
1,100
11,600
-17%
-38%
-19%
-28%
A2 WB offslip to RBT (excl.
new free-flow slip to M25)
RBT to M25 SB onslip (inc.
new free-flow slip to M25)
S
W
1,800
1,500
1,900
20,300
RBT to M25 SB onslip
(excl new free-flow slip to
M25)
300
200
200
2,600
1,900
1,400
2,000
20,100
6%
-7%
5%
-1%
1,000
800
1,200
11,100
-44%
-47%
-37%
-45%
M25 NB to RBT (exclude
existing free-flow slip to A2)
800
800
1,200
10,800
800
1,100
1,300
12,800
0%
38%
8%
19%
RBT to A2 WB (exclude
existing free-flow slip to A2)
700
500
700
6,900
600
400
500
5,600
-14%
-20%
-29%
-19%
1,600
1,300
1,700
17,500
1,400
1,100
1,500
15,100
-13%
-15%
-12%
-14%
RBT to new link road to J1b
800
500
1,100
8,700
RBT to A282 NB
500
300
300
4,500
A2 EB to RBT
N
% difference
both NB routes N of RBT
1,500
1,200
900
14,300
1,200
900
1,400
13,200
-20% -25% 56% -8% A282 SB to RBT
1,400
1,300
1,800
17,400
1,100
800
1,200
11,700
-21%
-38%
-33%
-33%
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
17
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Volumes of Traffic on Strategic network
2.24
The impacts on the traffic volumes on the M25 and A2 including the widened sections are
summarised in Table 2.5 and Table 2.6. Following the completion of the two schemes there was
considerable ongoing work on the communications infrastructure around the junction and on the
widened M25 and A2 especially including the preparations for the controlled motorway.
2.25
The key points regarding changes on the strategic network are:
A2

The widened section of the A2 between J2 and the Bean junction has shown significant
growth in both directions of 7-8% of weekday traffic. This suggests that the completion of this
scheme resulted in traffic growth despite of recessionary influences seen elsewhere. There
may also be traffic growth related to using data from 2010 rather than 2009;

In March 2010, average daily traffic (ADT) was 130,000 on the widened section;

West of J2 , traffic volumes have shown little change suggesting that the improvements at the
junction have not attracted traffic onto this route, but this may be expected as the scheme
has not made much improvements for traffic movements between the A2 west of the junction
and other arms; and

East of the widened A2, a paucity of data and the impacts of the Bean to Cobham schemes
makes it difficult to isolate any impacts of this scheme over the intermediate years.
M25 J2-3

The changes in traffic volumes on the M25 between 2006 and 2009 have been complex;

Post opening, average daily traffic (ADT) is 135,000 on the widened section; and

Traffic volumes on the widened section are effectively unchanged since before scheme
construction, which is similar to the no change seem on the section J3-4 south of the
improved section.
A282 / M25

The new layout between J2 and J1b in which the new link roads between the junctions are
completely separate from the main carriageway of the A282 has resulted in a large increase
in traffic using these links and a resultant drop in mainline traffic; and

Overall there appears to have been a drop in traffic of 7% northbound and 9% southbound
between J1b and J2. However it should be noted that this drop may be possibility attributable
to the limitations of the data used: single day video counts due to the lack of permanent
counts on these roads which would provide more robust data over a longer period.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
18
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.5 – Traffic on A2
Location
(shaded)
ADT
AWT
% difference
Directi
on
Scheme
location
2006
2009
2006
2009
ADT
AWT
WB
62,300
60,500
66,500
64,400
-3%
-3%
EB
63,900
61,400
67,900
64,500
-4%
-5%
WB
-
71,200
-
76,400
-
-
EB
-
70,900
-
75,700
within B259 junction
B255 to B259
A2/A282
scheme
-
-
68,700
1
6%
8%
1
4%
5%
64,300
1
62,800
65,500
1
65,900
68,900
WB
31,700
33,000
33,100
34,500
4%
4%
EB
31,200
-
32,900
-
-
-
WB
52,500
51,500
53,600
53,300
-2%
-1%
EB
55,700
56,700
58,300
59,300
2%
2%
WB
44,200
43,900
45,000
45,200
-1%
1%
EB
44,900
45,800
46,800
47,800
2%
2%
M25 J2 to Bean junction
(B255)
WB
EB
A2 Main Carriageway
beneath M25 J2
61,000
63,800
J2 to A2018
within A2018 junction
1
Post opening data is limited on this section, so March 2010 data was used, unfactored.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
19
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.6 – Traffic on M25
ADT
AWT
% difference
Directi
on
Scheme
location
2006
2009
2006
2009
ADT
AWT
NB
65,700
68,000
67,700
70,800
4%
5%
J1a - J1b
SB
68,500
69,600
71,700
72,900
1%
2%
A2/A282
J2 -J1b (exclude link road)
NB
64,100
55,6001
65,100
55,6001
-13%
-15%
M25 & A2/A282
J1b - J2 (exclude link road)
SB
65,400
54,1001
68,000
56,3001
-17%
-17%
A2/A282
scheme
J2-J1b link road
NB
10,000
14,7001
11,200
15,3001
47%
36%
J1b-J2 link road
SB
6,200
10,9001
6,600
11,3001
77%
72%
J2 -J1b (all roads) NB
74,000
70,3001
76,300
70,9001
-5%
-7%
SB
71,500
65,0001
74,600
67,6001
-9%
-9%
J3 - J2
NB
65,600
64,7002
68,100
66,7002
-1%
-2%
J2 - J3
SB
69,400
70,6003
73,400
73,6003
2%
0%
J4 - J3
NB
55,600
55,100
58,100
57,000
-1%
-2%
J3 - J4
SB
56,300
56,000
58,800
58,200
-1%
-1%
Location
J1b - J1a
J1b - J2 (all roads) M25 scheme
total
(shaded)
1
Post opening data is based on one day’s video count.
2
Post opening data is limited on this section, so March 2010 data was used.
2
Post opening data on this section is limited to only one full day in November 2009.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
20
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.7 – Traffic on local roads
2006
2009
% difference
Location
AM
PM
AWT
ADT
AM
PM
AWT
ADT
AM
PM
AWT
ADT
A296 Dartford East
WB
300
500
6,500
6,100
500
500
6,600
6,100
37%
1%
1%
-1%
(east of J1b)
EB
500
500
6,700
6,200
400
600
7,400
6,900
-20%
16%
11%
12%
A226 Dartford west
WB
500
500
7,200
6,800
500
500
6,500
6,300
-8%
-12%
-10%
-8%
(west of J1b)
EB
300
400
5,800
5,500
300
400
5,500
5,400
0%
4%
-4%
-2%
A225 South Darenth
SB
500
400
5,800
5,300
500
500
6,000
5,600
1%
11%
3%
5%
(parallel to M25 J2-3)
NB
400
600
6,300
5,700
400
700
6,700
6,200
-2%
17%
7%
8%
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
21
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 2.3 – Link Road between J1b and J2 RBT
Figure 2.4 – Link Road between J2 RBT and J1b
Volumes of Traffic on Local Roads
2.26
To examine whether impacts on nearby local roads can be identified, traffic count data was
obtained from Kent County Council as shown in Table 2.7.
2.27
The key points regarding changes in traffic volumes on local roads are:
2.28

The A296 immediately east of J1b, which can be used as a route to the Bluewater Retail
centre (opened 1999), and is approximately parallel to the widened section of the A2,
has shown some traffic growth in one direction only, suggesting that some traffic is
making journeys using the A296 eastbound and A2 westbound;

East of J1b, the A296 which links the junction to Dartford Town Centre has shown a
reduction in traffic, although this is not expected to be linked to these schemes; and

The A225, which is a minor A road parallel to the M25, and could therefore be an
alternative to the M25 for some local traffic shows no evidence of rerouting to the M25.
Hence, it can be concluded that there is no evidence that the schemes have reduced traffic on
local A roads parallel to the widened M25 and A2.
Figure 2.5 – M25 J2 – J1b / A282 and link roads (looking south)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
22
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Traffic flows through the day
2.29
Hourly traffic flows have been analysed to determine whether there have been changes to the
distribution throughout the day on the widened sections of the M25 and A2.
A2 between M25 J2 and Bean (widened section)
2.30
Post opening data for this widened section is only available from mid-December 2009 onwards.
Thus the best post opening data for use in this study has been taken from March 2010. This has
been compared with March 2006 data to provide the best comparison ignoring seasonal variation.
The difference in the 24 hour weekday traffic flows between these dates was 6% eastbound and
8% westbound. The 24 hour profiles are shown in Figure 2.6 and Figure 2.7.
Figure 2.6 – A2 westbound between M25 J2 and Bean hourly flows (weekdays in early March)
8000
March 2006
7000
March 2010
6000
5000
4000
3000
2000
1000
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Figure 2.7 – A2 eastbound between M25 J2 and Bean hourly flows (weekdays in early March)
8000
March 2006
7000
March 2010
6000
5000
4000
3000
2000
1000
0
1
2.31
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
The key points shown in the hourly of hourly traffic on the A2 are:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
23
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

On the section of the A2 east of the M25 the peak flows show a strong tidal element with the
busiest periods occurring on the AM peak westbound (toward London) and in the PM
eastbound;

Traffic growth in both directions has been greatest during the busiest peak periods. This
shows that peak period traffic is benefiting from the widening, as shown in the reduction in
congestion included later in this section.
M25 Northbound J3-2
2.32
Post opening data for this widened section covering more than a small number of days is only
available for July 2009 and February 2010 and at the time this study was compiled, early March
2010. Analysis of July ’09 and February ’10 data both showed reductions in traffic flows during
the interpeak period compared to the same months in 2005. However this data is affected by
February 2010 experiencing more snow disruption than normal, the effects of the London
bombings in July 2005 and the economic downturn. Thus, data was used from early March 2005
(excluding Easter) and early March 2010, as shown in Figure 2.8. Over 24 hours, the total flow is
down by 2% between 2005 and 2010.
2.33
The graph of the weekday hourly flows before and after the widening scheme shows that:

In the northbound direction, the highest flows continue to occur in the AM peak period; and

The small reduction in traffic flows has been spread throughout the day from 6:00 – 18:00
therefore there is no evidence that users have changed the times that journeys are made.
Figure 2.8 – M25 J3 - J2 hourly flows (weekdays in early March)
M25 Southbound J2-3
2.34
Southbound data in post opening period was only available for a single complete day in November
2009. Being based on only a single day means that conclusions from this may be less robust than
the above but these have been included for comparison purposes. The difference between the
total day’s flow on two selected days was a reduction of 1%.
2.35
The southbound hourly flow graph is shown in Figure 2.9. The main points from this are:

The highest hourly flows occurred in both the AM and PM peak periods, although the PM
peak is spread over a longer time period; and
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
24
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Although overall there was only a small reduction, in 2009, there was a reduction in the AM
peak flows 6;00 – 9:00 whilst there was growth in the PM peak (15:00 – 18:00). It is unclear
why this should have occurred.
Figure 2.9 – M25 J2 – J3 hourly flows (second Thursday of November)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
25
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Classified Data
2.36
Table 2.8 shows the weekday proportions of traffic longer than 5.2m in length in the period before
schemes construction and after where data is available. Note that the definition of HGV now
generally refers to vehicles longer than 6.6metres, but here 5.2m has been used because that
was the length classification used for the data collected during the before period.
Direction
Table 2.8 – Proportion of HGV traffic (>5.2m)
2006
2009
WB
-
-
EB
-
-
WB
-
26.5
EB
-
26.4
WB
15.9
15.4
EB
16.6
16.9
WB
-
-
EB
-
-
WB
13.5
13.3
EB
13.4
13.6
WB
13.1
13.2
EB
13.7
13.8
J1b - J1a
NB
23.5
-
J1a - J1b
SB
-
-
(from
J2 -J1b
NB
-
-
north
J1b - J2
SB
-
-
J3 - J23
NB
21.8
20.9
J2 - J3
SB
-
-
J4 - J3
NB
14.9
13.1
J3 - J4
SB
12.3
16.64
Road
Location
Weekday HGV %
(length >5.2m)
within B259 junction
B255 to B259
A2
(from
M25 J2 to Bean junction (B255)
east
to
west)
A2 Main c’way beneath J2
J2 to A2018
Within A2018 junction
M25
to
south)
2.37
The main points shown in this table are:

There has been negligible change in the proportion of larger vehicles on the A2; and
3
Data for J3-2 based on March 2005 and 2010 data.
Further analysis of the classified data at this site shows that the large increase in the proportion of vehicle
>5.2m here occurred in mid 2008 following a short period during which no data was available. The proportion
has remained consistently higher than the opposite direction since. This suggests that there is a calibration
issue with the count site. On the section J4-5, where classified data is only available for the after period, the
proportion of HGVs was 18.9% southbound and 17.4% northbound
4
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
26
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

On the M25 the pattern is mixed with a reduction on the northbound carriageway whilst there
has been an increase of four percentage points in the southbound carriageway. Reasons for
this disparity are unknown.
Journey Times
Sources of evaluation
2.38
2.39
Evaluation of the changes in journey times is based on observed data from a variety of sources:

Journey times on the main carriageway for the M25 and A2 were obtained using data from
the HA’s Journey Time Database (JTDB) in HATRIS. This provides data on average journey
times on a link by link basis between the primary junctions for all days and in 15 minute
intervals. This covered both the before and after periods; and

Journey times for turning movements at the M25 J2 are based on specially
commissioned surveys using the moving observed method. This is based on timing of trips
made by survey cars on the variety of movements possible at this junction. Data from the
2004 surveys undertaken by the scheme’s consultants for the appraisal was obtained for use
in this study to represent the before period. Moving observer surveys were commissioned for
the purpose of this study which covered the new movements possible at the junction in 2009.
It should be noted that the following findings on the change in journey times are all based on
mean journey times. These effectively average out the impacts of the not-infrequent ‘bad days’
where congestion is much worse than average. The impact on ‘bad days’ is considered later in
the evaluation of the reliability benefits standard deviation.
Journey Times on A2 main carriageway
2.40
For the purpose of this study, journey time data was extracted for June 2006 before the start of
construction, and June 2009, one year after opening. The available data for these periods is
identified in the database as being of varying quality across the months but only that identified as
high quality has been used here.
2.41
The time periods used here are weekdays during the following periods:
2.42

AM:07:00 – 10:00

IP: 10:00 – 16:00

PM: 16:00 – 19:00
Off peak journey times have been omitted due to low traffic flows.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
27
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.9 – Journey Times on A2
Section
Direction
Time period
Average Journey Time (seconds)
(weekdays)
2006
2009
Saving
A2 east of J2
WB
AM
180
154
26
(widened
section)
4.1km
IP
146
143
4
PM
143
143
0
EB
AM
159
156
3
4.3km
IP
163
157
6
PM
204
167
37
WB
AM
207
184
22
4.4km
IP
170
167
2
PM
168
170
-2
EB
AM
165
164
1
4.3km
IP
169
165
3
PM
196
172
24
A2 west of J2
Figure 2.10 – Average Journey times on widened A2 east of J2, eastbound
250
200
Seconds
150
100
June 2006
June 2009
50
06:00 ‐ 06:15
06:30 ‐ 06:45
07:00 ‐ 07:15
07:30 ‐ 07:45
08:00 ‐ 08:15
08:30 ‐ 08:45
09:00 ‐ 09:15
09:30 ‐ 09:45
10:00 ‐ 10:15
10:30 ‐ 10:45
11:00 ‐ 11:15
11:30 ‐ 11:45
12:00 ‐ 12:15
12:30 ‐ 12:45
13:00 ‐ 13:15
13:30 ‐ 13:45
14:00 ‐ 14:15
14:30 ‐ 14:45
15:00 ‐ 15:15
15:30 ‐ 15:45
16:00 ‐ 16:15
16:30 ‐ 16:45
17:00 ‐ 17:15
17:30 ‐ 17:45
18:00 ‐ 18:15
18:30 ‐ 18:45
19:00 ‐ 19:15
0
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
28
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 2.11 – Average Journey times on widened A2 east of J2, westbound
250
200
Seconds
150
100
June 2006
June 2009
50
06:00 ‐ 06:15
06:30 ‐ 06:45
07:00 ‐ 07:15
07:30 ‐ 07:45
08:00 ‐ 08:15
08:30 ‐ 08:45
09:00 ‐ 09:15
09:30 ‐ 09:45
10:00 ‐ 10:15
10:30 ‐ 10:45
11:00 ‐ 11:15
11:30 ‐ 11:45
12:00 ‐ 12:15
12:30 ‐ 12:45
13:00 ‐ 13:15
13:30 ‐ 13:45
14:00 ‐ 14:15
14:30 ‐ 14:45
15:00 ‐ 15:15
15:30 ‐ 15:45
16:00 ‐ 16:15
16:30 ‐ 16:45
17:00 ‐ 17:15
17:30 ‐ 17:45
18:00 ‐ 18:15
18:30 ‐ 18:45
19:00 ‐ 19:15
0
2.43
The key points shown in Table 2.9 and Figure 2.10 and 2.11 regarding changes in average
journey times are:

Journey time savings on the widened section, east of J2 are mainly in the peak periods of AM
for westbound traffic and PM for eastbound traffic. These are approximately ½ minute. This
reflects the highest flows as shown earlier in Figure 2.6 and Figure 2.7 and is clearly the
benefit arising from the widening of the road from three to four lanes; and

On the A2 west of J2 which was not widened there has also been savings in the peak tidal
period. This is likely to be the impact from reduced congestion at the junction.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
29
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Journey Times on M25 main carriageway
2.44
Journey times on the M25 have been analysed using the same method as for the A2 above.
Table 2.10 – Journey Times on M25
Section
Direction
Time period
Average Journey Time (seconds)
(weekdays)
2006
2009
Saving
J3 – 2
AM
224
160
64
NB
IP
204
194
10
PM
333
191
142
J2 – 3
AM
198
197
1
SB
IP
179
167
12
PM
185
164
21
AM
49
32
17
IP
42
40
1
PM
58
52
6
J1b – 2
AM
68
52
16
SB
IP
62
48
14
PM
63
47
17
Length
4.86km
4.94km
J2 – 1b
5
NB
0.94km
1.36km
Figure 2.12 – M25 J2-3 widened section
5
No high or medium quality data is available for the before period, so for J1b- 2, low quality has been used.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
30
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
18:45 ‐ 19:00
18:15 ‐ 18:30
17:45 ‐ 18:00
50
18:45 ‐ 19:00
18:15 ‐ 18:30
17:45 ‐ 18:00
17:15 ‐ 17:30
16:45 ‐ 17:00
16:15 ‐ 16:30
15:45 ‐ 16:00
15:15 ‐ 15:30
14:45 ‐ 15:00
14:15 ‐ 14:30
13:45 ‐ 14:00
13:15 ‐ 13:30
12:45 ‐ 13:00
12:15 ‐ 12:30
11:45 ‐ 12:00
11:15 ‐ 11:30
10:45 ‐ 11:00
10:15 ‐ 10:30
09:45 ‐ 10:00
09:15 ‐ 09:30
08:45 ‐ 09:00
08:15 ‐ 08:30
07:45 ‐ 08:00
07:15 ‐ 07:30
06:45 ‐ 07:00
06:15 ‐ 06:30
50
17:15 ‐ 17:30
16:45 ‐ 17:00
16:15 ‐ 16:30
15:45 ‐ 16:00
15:15 ‐ 15:30
14:45 ‐ 15:00
14:15 ‐ 14:30
13:45 ‐ 14:00
13:15 ‐ 13:30
12:45 ‐ 13:00
12:15 ‐ 12:30
11:45 ‐ 12:00
11:15 ‐ 11:30
10:45 ‐ 11:00
10:15 ‐ 10:30
09:45 ‐ 10:00
09:15 ‐ 09:30
08:45 ‐ 09:00
08:15 ‐ 08:30
07:45 ‐ 08:00
07:15 ‐ 07:30
06:45 ‐ 07:00
06:15 ‐ 06:30
Seconds
Seconds
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
450
Figure 2.13 – Average journey Times on widened M25 J3 – 2 (northbound)
400
350
300
250
200
150
100
June 2006
June 2009
0
Figure 2.14 – Average journey Times on widened M25 J2 – 3 (southbound)
450
400
350
300
250
200
150
100
June 2006
June 2009
0
31
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
2.45
2.46
The key points shown in Table 2.10, Figure 2.13 and Figure 2.14 regarding changes in average
journey times on the M25 are:

The biggest savings in journey time have occurred on the widened section J3-2 northbound
which has shown large improvements in the AM and PM peaks averaging 1 minute and 2 ⅓
minutes respectively, and limited evidence of improvement in the interpeak period;

J2 – 3 southbound, also widened, showed an improvement throughout the interpeak period
and a saving of ⅓ minute in the PM peak; and

On the much shorter section J1b – 2, there have been savings of ¼ minute on the widened
southbound section through the day.
It should be noted that the journey time data for both directions for J1b – 2 is labelled in the JTDB
as being of low quality for the before period which does not fully reflect the congestion problems
known to occur then. Data used for the other sections is all high and medium quality. Therefore,
it may be considered that the journey time savings observed here represent an underestimate of
the journey time savings on this section.
Journey times for turning movements at Junction
Surveys
2.47
Journey times for turning movements at the M25 J2 are based on specially commissioned surveys
using the moving observer method. This is based on timing trips made by survey cars on the
variety of movements possible at this junction.
2.48
Moving observer data is based on a more limited sample than the JTDB but it can still illustrate the
changes that have occurred for traffic making turning movements at the junction. Improving
journey times for this traffic was the key objective of the A2/A282 scheme.
2.49
The 2004 surveys covered movements which used the roundabout to make the right-hand turns
between the M25/A282 and the A2. Although this data did not directly cover other movements at
the junction, it did include detailed GPS tracking data of the surveys on a second-by-second basis.
For POPE analysis, this GPS data was analysed using GIS and associated software which
allowed for the construction of proxy journeys using micro segments of the observed data. This
allowed for coverage of all movements which used the circulating carriageway of the roundabout.
2.50
The only movement which was not observed and therefore could not be proxied was the use of
the single free-flow link which existed in 2004, which links the M25 northbound to the A2
westbound. This is the one part of the junction which was not altered in any way by the A2/A282
scheme so the omission of data here is not an issue.
2.51
The 2009 moving observer surveys covered:
2.52

Journeys using each of the three new free-flow links; and

Journeys making turning movements using the circulating carriageway of the roundabout.
The surveys covered the same time periods: AM, IP and PM as before.
Survey results
2.53
To evaluate the impacts, journey times were compared for traffic making each of the turning
movements. Where a free-flow link existed in the after period this was used.
2.54
The results from the journey time surveys in the AM and PM peak periods and the inter-peak (IP)
are summarised in Table 2.11. The movements for which traffic is now able to use the new freeflow links are indicated. Other movements use the roundabout (RBT).
2.55
Journey times for traffic in the after period making turning movements for which there is now a
free-flow link but they still travel via the RBT to make the turn have been omitted from this analysis
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
32
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.11 – Journey Times for movements around the junction
Time
period
A2 eastbound to
M25
southbound
From A282
north of
junction
A282
southbound to
A2 eastbound
A282
southbound to
A2 westbound
From M25
south of
junction
M25 northbound
to A2 eastbound
3:30
IP
3:10
PM
3:10
AM
3:00
IP
2:30
PM
2:20
AM
Time
-2:00
1:30
-1:40
Free-flow
link
west of J2
A2 eastbound to
M25 northbound
AM
Difference
Via
1:30
1:50
-1:10
1:40
-1:00
2:40
0:20
1:40
1:30
-0:10
IP
1:30
1:40
0:20
PM
1:30
1:40
0:10
AM
2:40
1:50
-0:50
2:40
2:10
-0:30
PM
2:30
1:50
-0:40
AM
2:10
1:30
-0:40
IP
2:00
1:20
-0:40
PM
3:30
AM
2:40
IP
2:30
PM
IP
RBT
From A2
Time
Free-flow
link
A2 westbound
to M25
southbound
(2009)
*
*
2:20
-0:10
2:10
-0:20
3:00
3:00
0:00
AM
3:10
2:50
-0:20
IP
3:10
2:40
-0:30
PM
4:00
RBT
east of J2
A2 westbound
to M25
northbound
RBT
From A2
After
(2004)
Free-flow
link
Via
Before
RBT
Origin
Turning
movement
*
*2009 PM peak period surveys on these routes were impacted by serious accident on day of
survey, hence have been omitted. Other journey times were measured the day previously.
2.56
Note that the movement M25 northbound to A2 eastbound is omitted from the above table. This
turning movement uses the only free-flow link which existed at the junction prior to the A2/A282
scheme and was not expected to be impacted by the scheme. Use of the free-flow link was not
included in the journey time surveys in 2004 and hence was also omitted from the 2009 surveys.
2.57
The changes are also summarised in the following figures.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
33
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 2.15 – Journey times from A2 east of J2
Figure 2.16 – Journey Times from A2 west of J2
Figure 2.17 – Journey Times from A282 north of J2
Figure 2.18 – Journey Times from M25 south of J2
2.58
The key points regarding changes to journey times for turning movements at the junction as
shown in the above tables and figures are:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
34
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

The largest observed improvement was for journeys using the new flyover which provides a
free-flow link between the A2 eastbound and the A282 northbound, replacing a 270° turning
movements around the signal controlled roundabout. This has shown savings of up to 2
minutes;

The journeys using the other two new free-flow links (A2 westbound to M25 southbound and
A282 to A2 westbound) have also shown large savings;

Some of the turning movements which still pass through the signalised carriageway of the
roundabout , i.e. that have not been directly changed by the scheme have also clearly been
shown to benefit from the lower level of traffic circulation on the roundabout (as shown in
Table 2.3). Of this traffic still on the roundabout, the one that particularly benefit are two of
the movements making a 270° turning movement:

-
A2 eastbound to M25 southbound; and
-
M25 northbound to A2 eastbound.
Little change was observed for movements in both directions using the roundabout to travel
between the A282 and the A2 west of the roundabout.
Traffic Forecasts vs. Outturn
Background to both schemes
2.59
The basis of the traffic modelling for the A2/A282 scheme and the M25 scheme was the existing
Kent Thames-Side (KTS) 2000 traffic model. This SATURN model was developed on behalf of
Kent County Council and other local authorities, including Dartford Borough Council, and was
made available to the Highways Agency for the purposes of the A2/A282/M25 traffic studies.
2.60
The forecast networks and demand include all committed and planned highway and development
schemes at that time, as discussed and agreed with the Highways Agency, and local authorities.
Local planning scenarios for developments and traffic restraint policies were also considered
when developing forecasting models for local developments. The forecasting process included:
2.61

Forecasts for future years using the National Trip End Model (NTEM) to apply growth factors
to travel movements within the study area;

Application of local growth factors from TEMPRO 4.3 to car-based trips;

Elastic assignment of trips to Do Minimum and Do Something networks to enable
assessment of induced traffic; and

Sensitivity testing of variable demand using DIADEM.
As there were a number of major public transport initiatives within the KTS area which were being
implemented during the appraisal and construction stages of these schemes, a high degree of
elasticity was modelled for competing trips. This particularly applies to:

Kent Thameside Fastrack Phase 1, a Bus Rapid Transport project comprised of 5.5 km of
dedicated and segregated busway between Dartford railway station to Bluewater Retail
Centre, completed in March 2006; and

Channel Tunnel Rail Link (CTRL), presumably using Ebbsfleet station.
A2/A282 Forecasts
Original scheme
2.62
The Original forecasts for the scheme at OPR stage were:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
35
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Traffic Forecasting Report 2002 OPR;

Micro Simulation report May 2003; and

Public Inquiry Traffic & Economics Proof of Evidence Summary (January 2002).
2.63
A key element of the basis of the modelling for the A2/A282 scheme was to take account of the
modelling of the adjacent A2 Bean to Cobham Phase 1 & 2 widening schemes. Although these
were undertaken by different consultants, a common approach was used for all. This was based
on an upgraded version of the 1993 Kent Thames Side (KTS) model. It was assumed that both
phases of A2 Bean to Cobham would be built.
2.64
The SATURN software was used for modelling the area wide traffic assignments and the microsimulation software GETRAM was used to assess the detailed vehicle interactions in the area of
the Scheme. Input traffic flows for GETRAM were provided by the SATURN traffic model.
2.65
The future traffic year forecasts were produced for the scheme taking account of the following
elements:

local and strategic traffic growth;

proposed developments;

reassignment effects; and

induced/suppressed traffic.
2.66
SCOOT data from the signals at the roundabout and TrafficMaster data on the A2 east of the
junction were reported in the Traffic and Economics Supplementary Proof of Evidence report
(2004) to show congestion regularly occurring at the junction and on the A2.
2.67
The assessment of induced traffic due to the scheme showed that the effects of trip induction or
trip suppression would be small for both low and high growth.
Revised scheme – Link E deferred
2.68
A summary of the revised modelling for the Link E deferred scheme was described in ‘A2/A282
Dartford Improvement Report on Deferment of Link E and Revised Landscape and Drainage
Attenuation Proposals in North West Quadrant of Junction 2’.
2.69
This report stated that the analysis using TRANSYT and micro-simulation (using AIMSUM) of the
junction concluded that under the high growth scenario, the revised layout would perform
satisfactorily at least until 2016. It was not considered to be practicable for high traffic growth to
continue beyond this time due to the limitations which would be imposed by the surrounding
network. Thus, assessment of the capacity of the interim solution beyond 2016 was been based
on 60:40 low to high growth – a recognized basis for junction design, and on low growth. Under
both scenarios, the analyses indicated that the proposed solution would perform satisfactorily up
to the design year.
2.70
The traffic programme ARCADY was used to test the option of operating the junction without
signal. This indicated that the junction would not operate satisfactorily as an uncontrolled
roundabout and that signals would be required.
2.71
The TRANSYT modelling for the original scheme indicated that under high growth forecasts, the
junction would operate adequately with signals at both the opening year 2007, and at the design
year 2022. With link E missing, the junction would still operate adequately in the design year with
low growth, but with higher traffic growth rates, congestion would occur earlier than the design
year.
2.72
No new traffic forecasts were included in the deferment report.
Evaluation of Forecast vs. Outturn with Scheme
2.73
The Traffic Forecasting Report gave forecast daily traffic (AADT) for the opening year of 2007.
For purpose of comparison with the observed data in this study, proxy 2009 forecasts were
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
36
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
calculated using a straight line growth assumption between the forecasts for the opening year and
design year of 2022. These proxy forecasts and the observed figures are compared in Table
2.12.
Table 2.12 – A2/A282 scheme: Forecast vs. Outturn AADT (2009)
% difference
Direction
Forecast
Low
growth
High
growth
Observed
Low
growth
High
growth
WB
59,700
65,900
67,300
13%
2%
EB
58,800
65,500
67,000
14%
2%
WB
47,800
51,000
51,500
8%
1%
EB
46,900
51,400
56,700
21%
10%
Flyover from A282 to A2
eastbound
16,000
18,600
16,600*
4%
-11%
Flyover from A2 westbound to
A282 northbound
16,500
19,200
15,600*
-5%
-19%
Dedicated slip A2 eastbound to
M25 southbound
12,800
13,600
11,700*
-9%
-14%
M25 J2 -3
NB
71,900
81,900
70,600
-2%
-14%
M25 J2 -3
SB
69,400
78,600
64,700
-7%
-18%
M25 J1b-2 & A282 link
roads
NB
77,300
89,300
70,300*
-9%
-21%
SB
74,700
85,500
65,000*
-13%
-24%
Location
A2 east of M25
A2 west of M25
*Observed data from 2009 is based on a single day
2.74
The key points are:

Traffic on the A2 has growth in line with the High growth forecasts;

One of the new flyovers , from the A282 to A2 east is as expected but the other two free-flow
links appear to be below forecast;

M25 traffic is well below all forecasts. As shown earlier, traffic has shown negligible growth
on this part of the M25 for several years, indicating that without the scheme, traffic would still
be below the modelled Do Minimum and that the forecast small increase on opening did not
occur; and

From this data, it appears that the economic recession has had strong influence on
dampening traffic growth on the M25 in line with wider regional trends whilst traffic growth on
the A2 has bucked the trend.
Evaluation of Forecast without scheme vs. Observed before scheme
2.75
In addition to comparing the forecast traffic flows with the scheme, the forecasts for the main links
without the scheme in what would have been the opening year (i.e. the Do Minimum scenario)
have also been compared with the observed data before the start of construction in 2006. These
are summarised in Table 2.13. Forecasts are as specified for 2007 without factoring and
observed data is also unfactored here. Note that 2006 observed data will not have been affected
by the recession.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
37
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.13 – A2/A282 scheme: Forecast Do Minimum (2007) vs. Observed before AADT (2006)
% difference
Direction
Forecast (2007)
Low
growth
High
growth
(2006)
Low
growth
High
growth
WB
53,900
58,900
61,000
13%
4%
EB
55,000
65,000
62,800
14%
-3%
WB
44,600
48,000
52,500
18%
9%
EB
44,800
48,200
55,700
24%
16%
M25 J2 -3
NB
68,700
79,500
65,600
-5%
-17%
M25 J2 -3
SB
68,500
77,800
69,400
1%
-11%
M25 J1b-2 & A282 link
roads
NB
70,500
81,000
74,000
5%
-9%
SB
71,100
80,900
71,500
1%
-12%
Location
Observed
A2 east of M25
A2 west of M25
The key points regarding the accuracy of the Do minimum forecasts are:

Before the A2/A282 scheme construction started, traffic growth on the A2 was near or above
the high growth forecasts;

Of particular note is that the traffic on the widened section of the A2 east of the M25 differed
form the forecast Do minimum by a similar proportion to that shown in Table 2.12 for the Do
Something forecast compared to the Observed data. This shows that the forecast impact of
the scheme on traffic growth on the A2 was accurate because the reason that the outturn
data was higher than predicted was due to growth between the time of appraisal and the start
of construction; and

M25 data was at the low end of the forecast range.
M25 J1b – 3 Forecasts
2.76
The M25 scheme was modelled with SATURN models which were based on those used for the
A2/A282 Dartford Improvement, with the base year model re-validated to 2004 using 2004 traffic
counts enhanced for the addition of the widened M25 J2 to 3 and also updated to include network
changes that had occurred up to 2004.
2.77
The modelled scenarios for this M25 J1b – 3 scheme were based around:
2.78

Do Minimum – no M25 scheme and no A2/A282 scheme (without link E); and

Do Something – both M25 scheme and A2/A282 scheme (without link E) completed.
An assessment of induced traffic due to the proposed improvement showed that the effects of trip
induction or trip suppression would be small; there would be a small increase in traffic flows
through the M25 corridor in the Do Something scenario compared to the Do Minimum.
Evaluation of Forecast vs. Outturn with Scheme
2.79
The M25 Stage 3 Scheme Assessment Report gave forecast daily traffic (AADT) for the opening
year of 2008. For the purpose of comparison with the observed data, proxy 2009 forecasts were
calculated using a straight line growth assumption between the opening year and design year of
2023. These are shown in Table 2.14.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
38
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 2.14 – M25 scheme: Forecast vs. Outturn AADT (2009)
% difference
Direction
Forecast
Low
growth
High
growth
Observed
Low
growth
High
growth
NB
80,800
89,400
70,600
-13%
-21%
M25 J2 -3
SB
74,000
83,500
64,700
-13%
-23%
M25 J1b-2 excluding link
roads
NB
71,000
80,300
55,600*
-22%
-31%
SB
69,900
78,200
54,100*
-23%
-31%
Location
M25 J2 -3
*Observed data from 2009 is based on a single day
2.80
The key points on the accuracy of the traffic forecasts are:

Observed traffic on this section of the M25 is substantially lower than the forecasts; and

Both low and high growth forecasts were based on growth from the base year traffic figures
of 2004/5 of between 2% and 23% but this clearly has not occurred.
Evaluation of Forecast without scheme vs. Observed before scheme
2.81
In addition to comparing the forecast traffic flows with the M25 scheme, the forecasts for the main
links without the scheme in what would have been the opening year (i.e. the Do Minimum
scenario) have also been compared with the observed data before the start of construction of the
A2/A282 scheme in 2006. These are summarised in Table 2.15. Forecasts are as specified for
2008 without factoring and observed data is also unfactored here.
Table 2.15 – M25 scheme: Do Minimum (2008) vs. Observed before AADT (2006)
2.82
% difference
Direction
Forecast (2008)
Low
growth
High
growth
2006
Low
growth
High
growth
NB
78,000
84,000
65,600
-16%
-22%
M25 J2 -3
SB
72,000
80,000
69,400
-4%
-13%
M25 J1b-2 excluding link
roads
NB
70,000
78,000
64,100
-8%
-18%
SB
68,000
77,000
65,400
-4%
-15%
Location
M25 J2 -3
Observed
The key points on the accuracy of the traffic forecasts are:

Clearly even without the two schemes, a high rate of growth was forecast for the M25; and

Allowing for the two year difference between the observed data in 2006 before construction
and the Do Minimum forecasts, it is clear that the traffic on the M25 was at the low growth
end of the range of traffic forecasts. Therefore the below forecast levels of traffic with the
scheme as shown in Table 2.14 are partly due to lower growth in the period before
construction which also predates the recession impact.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
39
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Journey Time Forecasts
A2/A282
2.83
There were no forecasts of journey time savings in the appraisal. Only matrix based results for
the whole network were specified. These cannot be compared to observed data.
M25 J1b – 3
2.84
As with the A2/A282 scheme, the appraisal was matrix based.
2.85
The Scheme Assessment Report (SAR) states that comparisons of modelled travel times in the
peaks and inter-peak periods in the M25 corridor indicated that there would be travel time savings
with the Scheme. Average modelled vehicle speeds were similar for M25 traffic for both the Do
Minimum and the Do Something models, despite the additional traffic. This is explained by the
increase in capacity of the motorway to absorb increased traffic flows during peak periods and
hence reduce congestion on the motorway section between junctions 1b and 3.
2.86
The SAR includes the following statements on the effect of the scheme on travel times:
2.87
2.88
2.89
Comparisons of modelled travel times for the three time periods indicated that there would
be travel time savings with the Scheme, which are translated into economic benefits ...
Average modelled vehicle speeds were similar for M25 traffic for both the Do Minimum and
the Do Something models. This is explained by the increase in capacity of the motorway to
absorb increased traffic flows during peak periods and hence reduce congestion on the
motorway section between junctions 1b and 3.
There are no further details on how the model derived travel time savings when the speed with the
scheme is similar to that without and there was only forecast to be a small increase in traffic flows.
However, the AST did include the following forecast under the wider economic benefits:
Average journey times between J1b and 3 would be reduced by 30-60 sec in 2008 …relative
to the baseline
The journey time savings detailed above indicate that savings have been 81 – 148 seconds
northbound and 16 – 38 seconds southbound in 2009. Therefore it is concluded that the forecast
saving has been achieved and have been exceeded for some time periods. The better than
expected time savings may be an impact of the lower than expected traffic growth.
Key Points from Traffic Section
Background recession
 This study has taken place against a background of the current recession which started in
mid 2008. DfT data for the wider road network in the South East and Kent showed no traffic
growth between 2006 and 2008 and provisional data for Great Britain shows that the
decline continued in 2009; and
 The impact seen on the strategic road network is also seen in long term trends on other
sections of the M25 which show negligible change in daily traffic between 2005 and 2009.
Impact on traffic numbers
 At the junction, the new free-flow links between the A282 and A2 east of J2 were used by
12,800 and 12,000 vehicles respectively in a 12 hour period on a weekday. The new link
between the A2 east and M25 south of J2 was used by 9,000 vehicles in 12 hours. The
flows on the new free-flow links equate to a total of 44,000 vehicles benefiting from these
free-flow movements per day;
 The new free-flow links have resulted in a reduction of a third in the volume of traffic at J2
using the circulating carriageway of the roundabout. This contributes to reduced congestion
of this traffic;
 The Widened M25 J2-3 is used by 135,000 vehicles daily, which is a negligible change from
that before the scheme;
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
40
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
 Changes to the layout of the A282/M25 J1b-2 has resulted in an increase in use of the link
roads between the junctions J1b – 2;
 Traffic on the widened section of the A2 is 130,000 AADT. It has shown growth of 7-8% on
weekdays. This has occurred particularly during the peak periods. This increase may be
partly explained by the completion of other schemes on the A2 east;
 There is no evidence that the schemes have reduced traffic on local A roads parallel to the
widened M25 and A2; and
 The proportion of HGVs (vehicles >5.2m) has shown little change following the completion
of the schemes.
Impact on Journey Times
 Journey times using the new free-flow links at the junction have improved by up to 2
minutes;
 For traffic still using the roundabout, journey times have improved for some turning
movements, particularly those making 270 degree right turns, and remained little changed
for others;
 On the widened A2, there was been a ½ minute saving in the AM peak westbound and PM
peak eastbound, reflecting the tidal flow on this road;
 On the M25, the biggest savings in journey time have occurred on the widened section J3-2
northbound which has shown with large improvements in the AM and PM peaks, averaging
1 minute and 2 ⅓ minutes respectively and an improvement in the interpeak;
 On the M25 J2 – 3 southbound, also widened, journey times showed savings through the
interpeak period and a saving of ⅓ minute in the PM peak; and
 On the much shorter widened section J1b – 2, there have been saving of ¼ minute on the
widened southbound section through the day but this is probably an underestimate due to
the limitations of the data on journey times in the before period.
Accuracy of Forecasts
 Traffic flow forecast for the A2/A282 scheme accurately predicted the growth on the
improved section of the A2. Before construction started, actual traffic growth was already
high and the recession did not slow this growth. It may also be that the impact of the
additional A2 widening schemes (Bean to Cobham phases 1 and 2) has contributed to
growth on the A2;
 Conversely on the M25, the traffic predictions for the scheme, which had shown growth both
with and without the scheme, have turned out to be overestimates. This can be linked to
growth being lower than forecast before scheme construction and the impact of the
recession post opening; and
 Journey time saving forecasts for the M25 have been achieved, and bettered for
northbound traffic.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
41
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
3.
Safety
Introduction
3.1
This section presents an evaluation of how the scheme is performing against the NATA safety
objective. WebTAG states that this objective is:

3.2
To reduce the loss of life, injuries and damage to property resulting from transport accidents
and crime.
The Safety Objective has two sub-objectives:

to reduce accidents; and

to improve security.
Data Sources
Accident data
3.3
For the purposes of this study, accident data has been obtained from the Managing Agent
Contractors (MACs) for the HA Area 4 (which includes the A2 in Kent) and Area 5 (which includes
the M25 including J2, the A282 and the section of the A2 west of the M25) for the periods:

Five years before start of construction: August 2001 to July 2006;

Eighteen months post opening: January 2008 to June 2009 for the whole area and

For the widened M25 only, 15 months of post completion data was obtained for Aug 2008 –
October 2009.
3.4
The construction period for these schemes have been excluded from the analysis as traffic flows
are not typical during this time period and the presence of traffic cameras will have affected driver
behaviour.
3.5
The accident data is based on the records of personal injury accidents recorded in the STATS19
data collected by the local police when attending accidents and collated by the local authority.
3.6
For comparison purposes, accident summary data for Kent CC roads was obtained from the Kent
Travel Report 2008.
3.7
The accident data referred to in this report has not necessarily been derived from the national
validated accident statistics produced by the DfT. As such, the data may subsequently be found
to be incomplete or contain inaccuracies. The requirement for up-to-date information and site
specific data was a consideration in the decision to use unvalidated data and, as it is sourced from
the Highways Agency’s Managing Agency Contractors, it is sufficiently robust for use in this
context.
Forecasts
3.8
The safety forecasts used in this evaluation are based on those given in the Stage 3 Scheme
Assessment Report (M25), Economic Assessment Report (A2/A282) and the schemes ASTs.
These were based on a spreadsheet analyses rather than a full COBA model.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
42
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Accidents
Scope of Accidents Analysis
3.9
Accident data was obtained for the wide area indicated on the left in Figure 3.1 covering the
sections of the strategic road network directly improved by the scheme and sections beyond:

A282/M25 between the southern slips for J1a and northern slips for J4; and

A2 between the junctions east and west of the M25 J2 (i.e. B255 and A2018).
Figure 3.1 – Accident study areas
3.10
3.11
Analysis of this accident data has been undertaken, split into the three areas shown in Figure 3.1:

Whole area of trunk roads based on the M25, A282 and A2 including the area directly
improved by the schemes and the sections of these roads beyond in each direction to the
next junction;

A2 improved by scheme, M25 J2 circulating roundabout and free-flow links, A282 and local
road links between J2 and J1b (shown in the right inset); and

M25 J2 – J3 both directions, excluding junctions (shown in the lower inset).
It should be noted that accident data for the local roads surrounding the strategic road network
was not collected and analysed. This was because although it was forecast that local roads in the
Kent Thameside area would experience safety benefits from some traffic rerouting onto the
strategic roads, this impact would be small and spread over a wide area over the long term. It
would not be feasible to identify these impacts derived from these schemes as distinct from many
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
43
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
other more significant factors impacting safety on local roads over a wide area in the 6½ years
studied. However, overall annual road traffic accident figures for Kent and the Dartford Area are
presented primarily for comparison purposes.
Wide area strategic road network (A2, A282 and M25)
3.12
The numbers of accidents in the wide area shown in Figure 3.1 over the before and after periods
are shown in Table 3.1.
Table 3.1 – Accident Numbers over Wide area network
Accidents by Severity
Total
Period
Fatal
Serious
Slight
(annual
equivalent)
2001 (Aug-Dec)
1
10
59
70 (168)
2002
4
18
160
182
2003
1
17
144
162
2004
2
11
157
170
2005
1
19
177
197
2006 (Jan-Jul)
2
7
92
101 (173)
Total 5 years before
11
82
789
882
2008
1
14
158
173
2009 (Jan – Jun)
3
4
72
Total 18 months after
4
18
230
Accident Saving
3.13
Annual Average
79 (158)
Fatal +
Serious
All
18.6
176.4
14.7
168.0
3.9
8.4
252
Key points regarding the accident numbers in the wider area based on the above data and Kent
CC data are:

The annual average accident total shows a small reduction (5%) between the before and
after periods;

However, this reduction in accident numbers on these strategic roads is similar to that
reported by Kent CC on the local authority roads in both the whole of Kent and in the Dartford
area only which both saw a reduction of 6% between 2003 and 2008; and

The reduction in both overall accident numbers and of the number of fatal and serious
accidents only is too small to be a statistically significant difference at this stage6.
Accident locations on routes within the two Schemes only (A2, A282 and
M25)
3.14
The locations of the accidents in the before and after periods on the sections of road directly
improved by each of the two schemes are shown in Figure 3.2 and Figure 3.3.
3.15
The high traffic volumes and long time periods mean that these figures show a large number of
accidents on the routes studied, but there are noteworthy points here:

6
Before the A2/A282 scheme was built, the greatest accident density on this network was
clustered around the junction, as would be expected;
Based on a Chi-square test using a 95% confidence level.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
44
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

In the 18 months following the opening of the A2/A282 scheme, the new free-flow links show
few accidents and the clustering around the circulatory roundabout is reduced; and

Accidents of the widened section of the M25 show no distinct pattern of clustering.
3.16
Detailed mapping of the locations of accidents at the junction was investigated but has not been
included here as they show little because of the density of accidents over the time period and
there are limitations in the accuracy of the locations in the data.
3.17
Analysis of the safety impacts is covered in more detail in the following sub-sections.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
45
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 3.2 – Accidents in five years before within the extents of A2 and M25 schemes
2001‐2006 Accidents
Fatal
Serious
Slight
Extent of Scheme
© Crown Copyright All Rights Reserved. Highways Agency 100018928.2010
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
46
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 3.3 – Accidents in 18 months (2008-mid 2009) within the extents of A2 and M25 schemes
2008‐2009 Accidents
Fatal
Serious
Slight
Extent of Scheme
© Crown Copyright All Rights Reserved. Highways Agency 100018928.2010
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
47
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Improved A2/A282/M25 J2 junction and widened A2
3.18
The numbers of accidents on the roads directly improved by the A2/A282 scheme only, as shown
in Figure 3.4, over the before and after periods are shown in Table 3.2.
Figure 3.4 – Area for A2 and junction accidents (M25 through J2 excluded)
© Crown Copyright All Rights Reserved. Highways Agency 100018928.2010
Table 3.2 – Accident Numbers over A2/282 scheme area only
Accidents by Severity
Annual Average
Total
Period
Fatal
Serious
Slight
(annual
equivalent)
2001 (Aug-Dec)
0
2
15
17 (40.8)
2002
2
6
56
64
2003
0
9
50
59
2004
1
2
49
52
2005
0
5
46
51
2006 (Jan-Jul)
1
1
21
23 (39.4)
Total 5 years before
4
25
237
266
2008
0
4
46
50
2009 (Jan – Jun)
0
1
17
18 (36)
Total 18 months after
0
5
63
68
Accident saving
3.19
3.20
1
Fatal +
Serious
All
5.8
53.2
3.3
45.3
2.5
7.9
Key points regarding the accident numbers on the improved A2 and the junction based on the
above data are:

The annual average accident total shows a reduction of roughly eight fewer accidents
including 2½ fatal or serious accidents; and

However at this stage this change is not statistically significant1.
Mapping of the locations of these accidents is shown in Figure 3.2 and Figure 3.3. These
pictorially show the density of accident clustering around the junction as expected. The after
mapping indicates that the free-flow links have a good safety record with few accidents.
Based on a Chi-square test at 95% confidence.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
48
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
3.21
We attempted to analyse the accident locations at a more detailed level at the junction but
unfortunately the detailed mapping of accident locations within the junction was not possible due
to limitations of the grid reference information in the available dataset.
Widened M25 J2 – J3
3.22
The M25 scheme was the widening of the section from J2 – 3 in both directions and the short
section of southbound carriageway between J2 and J1b. However due to the complexity of the
section north of J2 and the imprecision of some of the location data in the accident dataset,
accident numbers for J1-2 have been included in the above analysis and this sub-section only
considers the M25 main carriageway between J2 to J3 and through J2 as indicated in Figure 3.5.
Figure 3.5 – Area for M25 J2 – 3 accidents
© Crown Copyright All Rights Reserved. Highways Agency 100018928.2010
3.23
Note that no accidents are duplicated in Table 3.2 and Table 3.3.
Table 3.3 – Accident Numbers on M25 scheme area only
Accidents by Severity
Total
Period
Fatal
Serious
Slight
(annual
equivalent)
2001 (Aug-Dec)
0
1
5
6 (14.4)
2002
1
5
28
34
2003
0
3
29
32
2004
0
2
28
30
2005
0
2
22
24
2006 (Jan-Jul)
1
1
11
13 (22.3)
Total 5 years before
2
14
123
139
2008 (Aug-Dec)
0
0
8
8 (13.7)
2009 (Jan – Oct)
1
2
16
19 (22.8)
Total 15 months after
1
2
24
27
Accident saving
3.24
Annual Average
Fatal +
Serious
All
3.2
27.8
2.4
21.6
0.8
6.2
Key points regarding the accident numbers on the main carriageway of the widened M25 and
through the junction based on the above data are:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
49
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
3.25

The annual average accident total shows a reduction of roughly six fewer accidents, including
one fatal or serious accident in the after period compared to that before;

However at this stage this change is not statistically significant1.
Analysis of the locations of the accidents in Table 3.3 shows them to be distributed throughout the
length studied with no clear pattern between the before and after periods. The data does not
include lane information hence the pattern is effectively the same for the two periods. For this
reason maps showing these accident locations in the M25 widened section are not included here.
Combined Safety Impact of both schemes
3.26
The above tables have shown the accidents in the areas directly impacted by the schemes split
into the parts of the road network most impacted by each scheme. However it is clear that safety
impacts of the schemes are interlinked. For example, severe congestion at J2 can lead to traffic
queues stretching back to the M25 main carriageway creating a safety risk. In this case, the
junction improvements of the A2/A282 scheme could be expected to save accidents on the M25.
3.27
Additional analysis has been done to consider the combined safety impact of the two schemes.
This also provides a stronger base for statistical analysis.
3.28
Table 3.4 shows the total accidents within the areas of the two schemes. Note that unlike Table
3.1, this does not include accidents on the A2 or M25 beyond the boundaries of these schemes.
Table 3.4 – Accident Numbers on A2/A283 and M25 schemes area
Accidents by Severity
Annual Average
Period
Fatal
Serious
Slight
Total
Fatal +
Serious
All
Total 5 years before
Aug 2001-Jul 2006
6
39
360
405
9
81
Total 18 months after
Jan 2008 – Jun 2009
2
6
89
97
5.3
64.7
3.7
16.3
Accident saving
3.29
Key points regarding the overall accident numbers around J2 and the improved sections of the
M25, A2 and A282 are:

The annual average accident total shows a reduction of 16 fewer accidents , including nearly
four fatal or serious in the after period compare to that before; and

This overall impact of the two schemes combined has produced a large enough saving in
total accidents to be statistically significant2.
Forecasts
3.30
Normally, accident impacts for major highway schemes are appraised using the COBA modelling
software which forecast the saving in terms of both accident numbers and economic benefit
thereof. However, in the case of both of these schemes a spreadsheet approach was taken
instead and the results summarised in the appraisal reports. The details of the spreadsheet
appraisals were not available for this study.
3.31
The Economic Assessment Report (EAR) for the A2/A282 scheme explained the advantages for
using a spreadsheet approach. These were:
1
2
Based on a Chi-square test at 95% confidence.
Ibid
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
50
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

The analysis would have a direct connection with the SATURN model including the modelling
of congestion which would be very different from that modelled by COBA; and

COBA assumptions, accident rates and formulae could be used.
M25
3.32
The Stage 3 Scheme Assessment Report (SAR) stated that the safety objectives were to:

Reduce the number of accidents on the local road network; and

Minimise the number of reportable accidents and safety incidents during construction.
3.33
The appraisal included the assessment of the number and severity of accidents that would occur
with and without the Scheme. These were assessed by analysing the network flows and applying
default accident rates from the Department for Transport’s Cost Benefit Analysis (COBA) model.
The SAR did not include details of the scope of roads included.
3.34
The safety forecast in the AST was:
3.35
forecast Increase in accident rate on M25 J1b – 3 as a result of increase in traffic from
widening is more than compensated for by reductions in traffic on local roads from traffic
reassignment to M25, resulting in monetary benefits and overall reductions in accidents.
The AST did not detail the number of accidents forecast to be saved; only giving a range of
monetised safety benefits ranging from £0.9m to £4.2m. Using the default accident rates and the
accident values specified in the COBA manual1, it can be shown that the forecast accident saving
was equivalent to less than one per year.
3.36
Which of the local roads forecast to show a safety benefit from reassignment to the widened M25
was not specified. However it is presumed that that this refers to the A225 which is the only
North-south parallel A road in the area. The traffic forecasts (detailed earlier in Table 2.14) did not
include non-strategic roads so there is no forecast of the impact, and the observed change on this
road as shown in Table 2.7 was an increase. On this basis, it is not reasonable to attribute a
safety benefit on this A road due to traffic routed away.
A2/A282
3.37
The Economics Assessment Report (June 2002) describes the safety appraisal for this scheme.
This was based on a spreadsheet using the traffic flows in the opening year and design year
combined with accident rates from COBA which were applied as combined link and junction
accident rates. The EAR shows that the forecast accident saving in the opening year under both
high and low growth scenarios was three accidents.
3.38
The EAR was based on a 30 year appraisal period.
3.39
The Stage 3 Scheme Assessment AST stated that:
3.40
Improved junction layout to deal with peak-time queuing problem on A2 and M25 should
improve safety. (Figures include accidents saved in Kent Thameside area and exclude
accidents during maintenance and construction of Scheme.) A saving of 77 accidents was
forecast.
When the revised scheme (known as Link E deferred) was proposed in 2006, no reappraisal of
the safety impact occurred as it was considered that the change in benefits would be small. Only
the safety economic impacts were rebased. Therefore the 30 year appraisal period was retained.
Combined forecast vs. observed saving
3.41
The forecast opening year savings compared to the outturn are summarised in Table 3.5.
3.42
It should be noted that the forecasts were based on a wider area including Kent Thameside where
safety benefits were forecast based on the beneficial impact of some traffic reassignment to the
motorway network. Accident data for the local roads was not covered by this analysis because it
1
COBA manual, Part 2 The Valuation of Costs and Benefits
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
51
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
is clear that in the time period covered that it would to be unrealistic to reliably distinguish the
(forecast small) impact of the nearby schemes from many more local impacts.
Table 3.5 – Forecast vs. observed accident savings
Scheme
Forecast opening year
Saving
(including Kent Thameside)
A2/A282
Outturn Annual Saving
(scheme areas only)
3
16.3
M25 J1b – 3
below 1
3.43
This table of the findings of the observed accident data from the first 18 months shows that the
accident saving has been much better than the combined forecasts.
3.44
An explanation for this higher than expected accident saving in the post opening period may
reflect some temporary changes in driver behaviour following from the period during the
roadworks when traffic cameras were in force . At the time of the site visit in February 2010, a
camera sign could still be seen, as shown in Figure 2.5.
3.45
The POPE five years after evaluation will be able to examine the long term trend of the safety
impact.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
52
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Security
Forecasts
3.46
Forecasts of the security sub-objective impact are included in the AST for each scheme.
A2/A282
3.47
The AST states that the impact of the proposed CCTV coverage at J2 would be slightly beneficial
in terms of security.
M25
3.48
The AST states that there would be slight benefits to security as CCTV was incorporated
throughout M25 J1b to 3. Emergency call facilities would be improved compared to the existing
situation, a slight positive.
3.49
The SAR states that the provision of four CCTV cameras would ensure that the police could
monitor the road between J2 and J1b where the layout means that emergency phones could not
be installed.
Evaluation
3.50
10 CCTV cameras were installed at locations on the main carriageway of the M25 and A2, and at
the junction as planned.
3.51
It is understood from the contractors that most of these cameras were fully operational at the time
of this evaluation, although the commissioning of the communications infrastructure as part of the
wider works for the Controlled Motorway on the M25 was still being finalised. Images from several
of the cameras are publicly accessible from the trafficengland.com website. Figure 3.6 shows an
image from the camera next to the anti-clockwise carriageway approaching the slip road for J2. At
this location the CCTV enables the monitoring of a bridge section of the widened M25 where there
is now no hardshoulder.
3.52
It is concluded that the presence of the CCTV and emergency call facilities is slightly beneficial, as
expected.
Figure 3.6 – CCTV image of M25 and J2 southern slip road tie-ins
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
53
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Key Points from Safety Section
Impact on Accident numbers
 The numbers of accidents in the areas covered by the schemes has reduced in the post
opening period by an annual average of:

Eight accidents for the area covered by J2, the widened A2 and the A282/M25
J1b – 2; and

Six accidents for the widened section of M25 J2 – 3.
 Combined accident savings in the areas covered by the two schemes shows a statistically
significant saving of 20%.
 Small savings in the numbers of fatal and serious accidents have been observed although
at this stage it is too soon to determine the significance of these changes.
 An explanation for this higher than expected accident saving in the post opening period may
be that there was a continuance of the changes in driver behaviour from the period during
the roadworks when traffic cameras were in operation .
 The POPE FYA will be able to consider the safety impact with greater certainty.
Impact on Security
 The CCTV cameras have been installed as planned providing a beneficial impact to road
users as expected.
Accuracy of Forecasts
 The forecast savings in the number of accidents in the opening year for both schemes were
very low, hence it was not expected that a real change would be observed at this stage
since opening.
 However the saving in the first 18 months around J2 and over the widened sections of the
schemes shows a saving of 16 accidents per year which is a statistically significant
improvement and which is better than forecast.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
54
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
4.
Economy
Introduction
4.1
As described in the introduction of this report, the A2/A282 and M25 J1b – 3 schemes were
developed separately. The A2/A282 scheme was a standalone scheme prior any consideration of
the M25 scheme, and the M25 J1b-3 scheme originated from M25 rapid widening proposals which
included this as one the considered sections.
4.2
In early 2006, additional economic appraisals were undertaken for each scheme. These each
included consideration that the other scheme would be built. There was also appraisal for low and
high growth for each of four scenarios for the proposed variations to the approved version of the
A2/A282 scheme, namely:

Link E built and open in 2007 as previously planned;

Link E deferred to 2014;

Link E deferred to 2022, the design year; and

Link E deferred for whole evaluation period.
4.3
It was possible that the benefits to the Link E deferral from construction cost savings could be
offset by the extra vehicle travel time delays and accidents incurred by not building Link E.
4.4
The costs and benefits of the last three of the above scenarios are detailed below.
4.5
Additional to these two schemes, the M25 J2 – 3 Controlled Motorway scheme was separately
appraised in 2009. This is based on infrastructure put in place when this section of the M25
motorway was widened. It was not in operation at the time of this study so has not impacted the
findings presented here.
Economic Appraisals
A2/A282 Economic Appraisal
4.6
The original economic appraisal (A2/A282 Dartford Improvement Economics Assessment Report
Part 1 Methodology and Part 2 Economic Assessment) was issued in 2003 for the OPR.
4.7
Following a cost challenge review and proposal to modify the scheme by deferring the
construction of the free-flow Link E, a revised assessment was undertaken and was summarised
in the report A2 / A282 Dartford Improvement Economic Assessment Report Addendum II (June
2006). The review also updated the economic parameters in line with revised Government
guidelines. That is the appraisal period was revised from 30 to 60 years, the price base to 2002
prices and discounting changes to 3.5% for the first 30 years and 3% thereafter. This addendum
was the final appraisal prior to construction and has been used as the basis of this evaluation.
M25 J1b – 3 widening Economic Appraisal
4.8
The scheme was originally modelled as part of a wider study into the rapid widening of sections of
the M25 for opening year of 2011 and for scenarios with or without Road User Charging (RUC)
based on the NAOMI5 strategic model.
4.9
The Stage 3 Economics Assessment Report (EAR) addendum was issued in September 2006
and included an economic assessment of the M25 J1b to J3 Widening Scheme with Link E of the
A2/A282 Dartford Improvement Scheme deferred.
4.10
Modelling was based on TUBA v1.6c2 (Transport User Benefit Appraisal) using standard
economic parameter files and output from SATURN Model. This provided details of user benefits,
vehicle operating costs and revenue charges. The opening year was assumed as 2008 and the
horizon year 2067, providing for a 60 year assessment period.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
55
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
4.11
The time periods modelled were average morning peak hour, representing the period 0700 –
1000, average interpeak hour, representing the period 1000 – 1600 and average evening peak
hour, representing the period 1600 – 1900.
4.12
The approved EAR, dated September 2006 reported the benefits of the Scheme assuming full
implementation of the original version of the A2/A282 Dartford Improvement scheme, including
Link E, from 2007. However, an Addendum to the EAR, also dated September 2006, was issued
reporting the benefits of the M25 J1b to J3 Widening Scheme and reflected the revised proposal
for the A2/A282 scheme in which the construction of Link E at J2 would be deferred. This reflects
the as-built situation and hence has been used in this study.
M25 J2 – 3 Controlled Motorway (CM)
4.13
The appraisal of this additional scheme was reported in an Impact Assessment report in May
2009. This stated that it would cost £9.5m to build followed by a first year cost of £6m. Benefits
were assessed for 30 years as £31.4m based on observed impacts of CM on M25 J10-16.
Monetary benefits are derived mainly from accident savings.
4.14
At the time this study was completed, the CM was not in operation, therefore had had no impact
on the observed benefits of the widening scheme. Therefore, this is comparable with the
forecasts which did not include the CM in the appraisals.
4.15
The evaluation of the CM scheme is not covered by POPE.
Overall Appraisals Summary with various scenarios
4.16
Table 4.1 shows the alternative appraisals, excluding those which included Link E in the scheme
as completed in 2007, as that scenario did not happen. For each scenario low (LG) and high
growth (HG) were modelled in TUBA.
Table 4.1 – Appraisal of Monetised Costs and Benefits for A2/A282 under various scenarios
A2/A282 Dartford
Improvement
EAR II
Link E deferred
For full 60 years
LG
HG
to 2022
LG
to 2014
HG
LG
HG
Consumer User Benefits
£48.5m
£98.2m
£49.9m
£106.0m
£50.7m
£111.6m
Business User Benefits
£67.5m
£110.7m
£76.0m
£123.3m
£78.6m
£130.3m
Private Sector Provider Impacts
£18.8m
£14.3m
£20.5m
£19.9m
£21.2m
£20.8m
£1.8m
£0.0m
£1.8m
£0.0m
£1.8m
£0.0m
£136.7m
£223.2m
£148.2m
£249.2m
£152.3m
£262.7m
Investment
£97.3m
£97.3m
£103.2m
£103.2m
£104.9m
£104.9m
Indirect tax
£4.1m
£5.8m
£4.9m
£8.1m
£4.9m
£8.7m
£101.3m
£103.0m
£108.1m
£111.3m
£109.7m
£113.6m
Net Present Value
£35.3m
£120.1m
£40.2m
£137.9m
£42.6m
£149.1m
Benefit to Cost Ratio
1.35
Accident Benefits
Present Value of Benefits
Present Value of Costs
4.17
2.17
1.37
2.20
1.39
2.31
This clearly shows that delaying the construction of Link E was forecast to impact the economics
of the A2/A282 scheme by:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
56
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Reducing the benefits slightly;

Reducing the costs slightly; and

Reducing the BCR slightly.
4.18
For this scheme, the model shows large private sector provider benefits. The EAR states that this
is the revenue gained by the operators of the Dartford Crossing. Equivalent amounts are
disbenefits deducted from the consumer and business user benefits total as shown above. No
further details are provided.
4.19
Indirect taxation represents the change in the government’s taxation revenue as a result of a
scheme. In the case of this scheme, the model forecast that changes in traffic behaviour would
result in a reduction tax being raised. In such a case where there is neither change in road length
nor a drop in traffic levels, this would be as a result of greater fuel efficiency due to reduced
congestion.
4.20
For the M25 scheme, Table 4.2 similarly shows how the economic forecasts were impacted by the
alternative scenarios for growth and for the link E in the A2/A282 scheme, excluding that which
included Link E in the scheme as completed in 2007, as that did not happen. For each scenario
low (LG) and high growth (HG) were modelled in TUBA.
4.21
Note that modelling was based on comparing a Do Something scenario with both schemes
completed against a Do Minimum with neither.
Table 4.2 – Appraisal of Monetised Costs and Benefits for M25 J1b-3 under various scenarios1
M25 J1b-3 widening
EAR II
Link E deferred (on A2/A282 scheme)
For full 60 years
LG
LG
to 2014
HG
LG
HG
Consumer User Benefits
£51.2m
£110.7m
£52.3m
£112.2m
£52.7m
£120.5m
Business User Benefits
£75.5m
£171.2m
£81.9m
£175.1m
£85.4m
£192.0m
Private Sector Provider Impacts
£0.5m
£6.4m
-£0.5m
£12.6m
-£0.5m
£12.1m
Accident Benefits
£0.9m
£4.2m
£0.9m
£4.3m
£0.9m
£4.3m
£128.2m
£292.5m
£134.6m
£304.2m
£138.5m
£328.9m
Investment
£65.3m
£65.3m
£65.3m
£65.3m
£65.3m
£65.3m
Indirect tax
£1.5m
£6.3m
£4.2m
£8.3m
£4.8m
£9.7m
Present Value of Costs PVC
£66.8m
£71.6m
£69.5m
£73.6m
£70.1m
£75.0m
Net Present Value
£61.3m
£220.9m
£65.1m
£230.6m
£68.4m
£253.9m
Benefit to Cost Ratio
1.92
Present Value of Benefits PVB
4.22
1
HG
to 2022
4.09
1.94
4.13
1.98
4.39
This shows that the economics of the M25 J1b-3 scheme were forecast to be impacted by the
deferral of the construction of Link E in the A2/A282 scheme by also:

Reducing the benefits slightly;

Reducing the costs slightly, through changing the indirect tax impact; and
All values are discounted present values in 2002 prices and values.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
57
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

4.23
Reducing the BCR slightly.
For the remainder of this chapter, the full deferral (i.e. by 60 years) of Link E has been assumed,
as this option:

Can be based on observed traffic and accident data without Link E;

Allows comparison of the forecast and outturn cost of the scheme without considering the
future cost of Link E; and

Provides the most conservative estimate of benefits.
Transport Economic Efficiency
Evaluation of TEE benefits – Summary of Approach
4.24
4.25
Benefits to business users and consumers in the Transport Economic Efficiency (TEE) component
of the TUBA model emerge from the following:

Vehicle Operating Costs (VOCs); and

Vehicle Hour Savings i.e. Travel Time benefits.
For major highways schemes, changes to VOC savings constitute the minority of the TEE
benefits. For these schemes, there were forecast savings in VOC for users for the A2/A282 whilst
there were increases in VOCs for users of the M25 scheme. These impacts comprised only a
small proportion of the overall TEE. Furthermore, given that the scheme’s impact on VOCs is
difficult to measure using observed data, evaluation of this impact is not typically included as part
of POPE.
POPE Methodology
4.26
4.27
Based on the POPE evaluation of numerous other schemes across the national network we have
found that a majority of scheme benefits are derived from two sources:

Link Transit Time (vehicle hour) benefits which provide economy benefits; and

Reduction in accident numbers providing monetised safety benefits.
The basis of the POPE methodology (in terms of vehicle hour savings) is a comparison of
changes in total link transit times before and after scheme opening using observed journey times
and traffic flows and applying this ratio to the predicted savings. As such this method is most
commonly applied to schemes that have been appraised using COBA software. Vehicle hour
savings for both the A2/A282 and M25 schemes were appraised using TUBA software. TUBA
modelling is based on Origin-Destination matrices, and is clearly a more appropriate modelling
tool for the schemes of the complexity here. Also important here is modelling growth and
elasticity. However, a TUBA model cannot be used as the basis of a post opening evaluation
without replicating the whole modelled area which is logistically and financially not feasible. As
TUBA output does not report impacts on a link basis it is not possible to extract a subset of traffic
impacts to compare against the observed data. Hence the POPE methodology is not suitable for
the OYA evaluation of these schemes.
PAR Methodology
4.28
1
As an alternative approach, the journey time benefits for these schemes have been evaluated
using a PAR approach, typically adopted by the HA for the appraisal of smaller schemes1. This
evaluation is therefore subject to a number of caveats and assumptions as listed below:
PAR Guidance Project Appraisal Report Guidance Notes Version 5.0
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
58
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

The evaluation only includes journey time savings on the A2 and M25 corridors, and the
junction and not the wider network. The appraisal however was based on these strategic
roads and those in the Kent Thameside Area. Thus this evaluation is missing potential
benefits in the wider area;

The impact of future development in the Kent Thameside Area (as modelled in the appraisal)
is not considered;

This evaluation only considers the impact of the scheme with Link E deferred indefinitely (60
years);

The PAR method provides capitalisation factors which depend only on the road type and
forecast growth rate whereas modelling tools used for the appraisal consider the complexity
of how traffic growth would affect future traffic behaviour in detail. For these schemes, future
forecasts will be influenced by timing and severity of forecast congestion with or without the
scheme. For example, with high growth traffic, the modelled benefits could be heavily based
on the early part of the appraisal period; and

The impact of the CM on the M25 widening is omitted.
How modelling assumptions affect schemes jointly
4.29
4.30
In the case of both schemes evaluated in this study, the final economic appraisals were based on
modelling assumptions of the scenarios:

Do Minimum – neither scheme built; and

Do Something – both schemes built.
This means that there is no double-counting of the benefits across the two economic forecasts.
Hence, it is reasonable to sum up the benefits to get a total across the two.
PAR Evaluation of TEE
Forecast
4.31
The forecast TEE savings for each scheme using this method are summarised in Table 4.3.
Table 4.3 – Predicted TEE Benefits from TUBA
Scheme
LG
HG
50:50 Midpoint
A2/A282
£134.8m
£223.2m
£179.0m
M25 J1b - 3
£127.2m
£288.3m
£207.8m
Total
£386.8m
4.32
Over 60 years post opening with average growth rates, the A2/A282 was forecast to deliver
£179m of TEE benefits and the M25 J1b-3 would deliver £207.8m.
4.33
This gives an overall total benefit of £386.8m.
Evaluation
4.34
The PAR method of calculating the TEE journey time benefits is based on the vehicle hours saved
in the first year, monetised by using a Value of Time (VOT) then converted to a forecast for the
whole appraisal period using capitalisation. Values for the VOT for an average vehicle per hour
and capitalisation factors are specified in the PAR guidance.
4.35
It is not possible to use TUBA outputs to create a comparable forecast based on the impacts on
the same corridor, as TUBA is matrix based and its output does not give any breakdown of the
impacts by link or area.
4.36
Therefore, for the evaluation of the selected links, vehicle hours saved in the opening year were
calculated using the observed traffic flows and journey times described in the traffic section
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
59
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
extrapolated to a full year based on the AM, IP and PM weekday time periods as used in the
appraisal. The vehicle hours covered the following links:

M25 J2-3 (both directions);

A2 Bean to M25 J2 (both directions); and

Turning movements at J2 – both free-flow and using the roundabout.
4.37
This list covers all the improved sections with the exception of the short section M25 J1b-2
mainline carriageway where there is limited data. As this section covers less than 1km, this is
only a small part of the overall journey time changes.
4.38
The benefits accrued by additional traffic were calculated at 50% of those for the existing traffic,
according to the ‘rule of half’.
4.39
The calculation of the journey time benefits for each scheme using this PAR method are
summarised in Table 4.4.
Table 4.4 – Outturn TEE Benefits from PAR method
Scheme
Annual Vehicle
Hours
VOT
(2009)
60 year benefits
(capitalised from
2009)
(2009)
A2/A282
264,233
£12.86
£169.5m
M25 J1b - 3
251,296
£12.86
£161.2m
Total
£330.7m
4.40
Because this evaluation is based only on the benefits for traffic on the improved sections of the A2
and M25 and at the junction, compared to the much wider area used in the TUBA models, it is
likely that the figures in Table 4.4 represent underestimates of the benefits to the wider area.
Furthermore, it is likely that some benefits are also accrued during the off-peak periods which are
not included here.
4.41
The summary of the comparison between forecast and outturn TEE benefits are shown in Table
4.5.
Table 4.5 – Forecast vs. Outturn TEE Benefits
Scheme
Forecast
Outturn
%difference
A2/A282
£179.0m
£169.5m
-5%
M25 J1b - 3
£207.8m
£161.2m
-22%
Total 60 year TEE benefits
£386.8m
£330.7m
-14%
4.42
This shows that evaluation of these schemes using observed data and a simple methodology still
supplies a substantial TEE benefit. Considering that these outturn figures only cover a narrow
area, they give estimates of the outturn TEE benefits which are nearly as high as those forecast,
especially for the A2/A282 scheme.
4.43
Reasons why the Outturn TEE in Table 4.5 are lower that forecast include:

Forecast includes benefits from whole Kent Thameside area as opposed to key links only in
the outturn;

Observed M25 traffic is lower than was forecast; and

Although A2 traffic was higher than predicted, the observed journey time savings were fairly
small and may be lower than the modelled journey time difference quantified into monetary
benefits within TUBA.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
60
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Monetised Safety benefits
4.44
The monetary benefits emerging from changes in safety are calculated by assigning monetary
values to the reduction in the number and severity of personal injury accidents over the appraisal
period.
M25 Forecast
4.45
Accident savings were evaluated using a spreadsheet based on COBA (Cost Benefit Analysis)
figures. This was used to predict the number of accidents and accidents by severity in the future.
4.46
The AST states that the Increase in accident rate on M25 J1b – 3 as a result of increase in traffic
from widening is more than compensated for by reductions in traffic on local roads from traffic
reassignment to M25, resulting in monetary benefits and overall reductions in accidents.
4.47
The economic value ranged from £0.9m at low growth and £4.8m high growth as shown in Table
4.2. The area covered by this spreadsheet appraisal was neither detailed in the appraisal
documentation nor the distribution of the benefits over the 60 year period. What can be deduced
from this is that the opening year impact would be less than two accidents which is a figure too
low to be able to distinguish from random variation with any statistical confidence.
A2/A282 Forecasts
4.48
The Traffic & Economics Proof of Evidence (2004) presented safety forecasts based on two
different approaches based on spreadsheets, rather than COBA. These were:

Default values for accident rates and costs from COBA, for both the Do Minimum and Do
Something scenarios. As there is no difference between COBA accident rates for dual 3 lane
motorways and dual 4 lane motorways, the increase in traffic in the Do Something case
forecasts resulted in an increase in the number of accidents on the A2. However these
additional accidents were offset by an expected reduction in accidents elsewhere on the road
network caused by a reduction in traffic levels. Forecast economic benefit was £0.85m for 30
years at 1998 prices. This was considered to be the conservative estimate of the benefits;
and

Observed accident rates were used for the Do Minimum accident rates and COBA accident
rates used for the Do Something. As the observed rates in 1996 – 2001 were significantly
higher than the number of accidents expected using the COBA rates, this gave benefits of
£22m.
4.49
The conservative estimate was used because it was not expected that the full benefit predicted
using the COBA rates would be realised due to the complex nature of the layout of this junction
meaning that there would still be a significant remaining number of merges and diverges.
4.50
The 2006 appraisal was simply a rebasing of the earlier conservative figure, and remained as
being based on the assumption that safety benefits would only occur in the first 30 years. Note
that unlike the TEE benefits, this appraisal period was not changed to 60 years and it was stated
that it was not expected that safety benefits would extend beyond the 30 years.
Summary of Forecast safety benefits.
4.51
Table 4.6 summarises the benefits for each scheme and in total. Note that these exclude the
impacts of:

Link E as part of the A2/A282 scheme, as shown in Table 4.1 and Table 4.2. This makes
negligible difference in the forecasts for both schemes; and
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
61
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Controlled Motorway on the M25 J2-3, which was appraised separately in 2009 to produce
£23m in safety benefits1 which was also not included in the 2006 appraisals of either of these
schemes.
Table 4.6 – Forecast Monetised Safety Benefits
Scheme
LG
HG
50:50 Mid-point
A2/A282
£1.8m
£0
M25 J1b-3
£0.9m
£4.2m
Total
£2.8m
£4.2m
£3.5m
Evaluation
4.52
The spreadsheet used for the appraisal of the safety benefits was not available for use in this
evaluation.
4.53
The chosen method for the evaluation in POPE where details of the forecast are not available is to
use aspects of the PAR method which is based on the standard HA method defined for simpler
schemes. The PAR method is based on an estimate of the opening year accident saving being
monetised to a long term benefit. For post opening evaluation here, the method is based on the
observed changes in the number of accidents within the boundaries of the schemes on the M25
and A2 corridors.
4.54
Note that this method does not consider observed savings by accident severity as the numbers
are too low to be significant.
4.55
The accident savings for the post opening period converted to annual figures, as shown in Table
3.2 and Table 3.3, have been monetised according to the type of road which is related to both the
value of an accident and how the benefits are expected to be valued over the whole appraisal
period i.e. capitalisation. National average growth was assumed. As noted above, the forecast
only considered benefits in the first 30 years. This time period has been also used for this
evaluation as shown in Table 4.7.
Table 4.7 – Outturn Monetised Safety Benefits
4.56
Value of an
average
Accident in
scheme
opening year
by road type
30 year
capitalisation
factor
30 year
outturn
benefit
A2/A282
6.2
£89,850
26.6
£14.8m
M25 J1b-3
7.9
£83,400
34.1
£22.4m
Total
14.1
-
£37.3m
The limitations of the above calculations are:

1
Scheme
Annual
Accident
Saving
(observed)
This is based on the layout of the road network on completion of the two schemes. It does
not include:

The completion of Link E at any time;

The impact of the Controlled Motorway, which is expected to be in operation later
this year and hence for the majority of the 30 years covered in this outturn
Impact Assessment M25 Junctions 2 to 3 Controlled Motorway, May 2009
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
62
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
calculation, is not included in this evaluation, but nor was it considered at the
appraisal;

Growth on the M25 has been below national trends in recent years; if this continues in the
long term, then based on this method, the safety impact would be expected to be lower,

Only the area within the schemes and the whole of J2 has been included, thus this omits any
benefits which may arise in the wider area including the local roads; and

The safety impact of future congestion with or without the scheme, especially linked to the
use of the junction is not modelled by the simple PAR method.
4.57
As shown in the safety section of this report, accidents were mainly clustered around J2, as would
be expected. These have nominally been classified as A2/A282 accidents in this evaluation, but
clearly the M25 scheme can also influence safety at the junction, therefore totalling the overall
outturn benefit is reasonable.
4.58
The summary of the comparison between forecast and outturn safety benefits is shown in Table
4.8.
Table 4.8 – Forecast vs. Outturn Safety Benefits
Total 30 year safety benefits
Forecast
Outturn
£3.5m
£37.3m
4.59
This shows that outturn safety benefits of the two schemes combined are 10 times higher than
forecast.
4.60
The much higher than expected accident saving in the post opening period may reflect some
temporary changes in driver behaviour following on from the period during the roadworks when
traffic cameras were in force.
Summary of Present Value Benefits
4.61
Overall Present Value Benefits are summarised in Table 4.11.
Table 4.9 – Present Value Benefits (£m)
TEE
Safety
Total
Scheme
Forecast
Outturn
Forecast
Outturn
Forecast
Outturn
A2/A282
179.0
169.5
0.9
14.8
179.9
184.3
M25 J1b-3
207.8
161.2
2.6
22.4
210.4
183.6
Total
386.8
330.7
3.5
37.3
390.3
368.0
Scheme costs
4.62
This section compares the forecast costs of the two schemes with the outturn.
4.63
The outturn cost does not include the costs of the Controlled Motorway (CM) works undertaken at
the same time as the M25 widening scheme. This evaluation is based on the widening scheme
benefits prior to the activation of the CM.
4.64
The EAR Addendum for each scheme from 2006 gave the following details for each scenario for
each scheme:

Investment cost;

Indirect Tax impact; and
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
63
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Overall Present Value Costs
4.65
All were given in 2002 prices, discounted to 2002. Although not explicitly stated in the report, it is
assumed these were in market prices. No breakdown of the spend profile was available but as
the schemes were constructed within the planned time period, no adjustment was necessary.
Present Value Costs are on the same basis as Present Value Benefits and therefore are used to
calculate the Benefit Cost Ratio.
4.66
To compare the forecast investment cost with the as-spent cost, the market price factor was
removed from the investment costs, and discounting also removed.
4.67
The outturn spend profile for this scheme has been obtained for the purpose of this study from the
HA regional finance manager. The as-spent figures for the period 2000 – 2009 have been
converted to 2002 prices. This figure can then be compared with the forecast cost on a
comparable basis, as shown in Table 4.10.
Table 4.10 – Investment costs
4.68
Scheme
Forecast, no Link E
Outturn
% difference
A2/A282
£94.2m
£105.7m
12%
M25 J1b-3
£65.5m
£49.9m
-24%
Total
£159.6m
£155.6m
-3%
This comparison of costs indicates that whilst the A2/A282 scheme costs were above that
predicted, the M25 widening was below forecast. As the two schemes were under construction at
the same time, it is valid to combine the costs and summarise that the total cost was just below
the forecast.
Indirect Tax
4.69
The Central Government Funding includes the reduction in the indirect taxation the Government
would have received from users of the scheme.
4.70
The forecast impact of indirect taxation made up 5% of the A2/A282 PVC and 6% of that of the
M25, assuming mid-point growth.
4.71
These figures are calculated by TUBA based on traffic behaviour over the whole appraisal period
but no details of the basis are available. As the route lengths are similar, it is assumed that this
reduced taxation represents a general improvement in vehicles travelling at more fuel efficient
speeds.
4.72
It has not been possible to evaluate the indirect tax impact based on observed data due to limited
data on the basis of the forecast (i.e. area and speeds) and the profile of how future congestion
with or without the scheme would affect speeds.
4.73
Hence it has been necessary to assume that the forecasts are accurate and this is deemed
reasonable on the basis that it is only a small part of the overall impact here.
Summary of Present Value Costs
4.74
Present Value Costs including indirect tax are summarised in Table 4.11.
Table 4.11 – Present Value Costs
Forecast, no Link E
Outturn
A2/A282
£102.2m
£115.9m
M25 J1b-3
£69.2m
£54.6m
Total
£171.4m
£170.5m
Costs in £m 2002 prices
discounted to 2002 at 3.5%
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
64
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Benefit Cost Ratio
4.75
The Benefit-Cost Ratio (BCR) is used as a summary of the overall value for money of a scheme.
Using the economic benefits (PVB) and costs (PVC) detailed above, the forecast and outturn BCR
can be compared as shown in Table 4.12.
Table 4.12 – Forecast vs. Outturn Benefit Cost Ratio
Combined schemes
TEE
Present Value Benefits (PVB)
Safety
Total PVB
Present Value Costs (PVC)
Benefit Cost Ratio
Forecast
Outturn
£386.8m
£330.72m
£3.5m
£37.3m
£390.3m
£368.0m
£171.4m
£170.5m
2.3
2.2
4.76
This shows that despite the TEE benefits being 14% lower than forecast, the much better than
forecast safety benefits combined with the slightly lower costs have meant that the BCR is 2.2
which is virtually as predicted.
4.77
The combined BCR above for the two schemes combined meets the DfT criteria for high Value for
Money; therefore this evaluation confirms that these schemes represent a good return on
investment over 60 years.
4.78
It should be noted that the BCR ignores non-monetised impacts. In NATA assessments, the
impact on environmental, accessibility and integration objectives must be assessed but are not
monetised. The evaluation of these three objectives is covered in the following sections.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
65
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Route stress/ Journey Time Reliability
A2/A282
Forecast
4.79
The Inspectors report noted that the need for the scheme included the existing problem of high
traffic levels leading to significant delays and unreliable journey times, especially at peak times
and/or following a traffic incident in the area.
4.80
The AST stated that the scheme should improve reliability due to improved flow through M25 J2.
No quantitative measure is given.
4.81
The Economics Assessment Report (2004) gives no monetised value for reliability.
Evaluation
4.82
POPE methodology for the evaluation of reliability is currently under review.
4.83
Reliability is concerned with travel time variability or journey time variability. Thus a proxy for
reliability can be obtained by examining the variation within journey times in the before and after
periods using the journey times in the JTDB, as used in the traffic section of this study. The metric
used is standard deviation of journey times from the mean time for each time period in the before
and after periods. In each time slice, the average time is made up of many individual results. The
larger the deviation of the individual journey times from the mean journey time, the greater the
unreliability. The difference in the standard deviation in the before and after periods is shown
graphically in Figure 4.1 and Figure 4.2 for weekday journey times on the widened section of the
A2.
Figure 4.1 – Standard Deviation of Journey Times A2 (A296 to M25, westbound)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
66
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 4.2 – Standard Deviation of Journey Times A2 (M25 to A296, eastbound)
4.84
The above graphs show that the standard deviation of journey times on the widened section of A2
was reduced in the after period. This indicates improved reliability of journey times.
M25 J1b - 3
Forecast
4.85
The SAR (Nov 2006) stated that at that time, there was no established software for estimating the
reliability of journey times from reductions in incidents for a road scheme, so the accepted
alternative was the assessment of route stress. This compares the AADT to a theoretical
measurement of congestion called the Congestion Reference Flow. It was forecast that the
scheme should improve reliability due to a reduction of delays as a result of the widening.
4.86
However the calculation of the route stress using this method gave values for the sections of the
M25 within the scheme, even in the Do Minimum scenario, of below 0.75 which according to the
webTAG guidance, indicates that journey time reliability was not a significant concern, which
clearly contradicted the known problems at that time. Hence, the AST stated that this approach
did not provide a direct quantification of changes in reliability or reliability benefits.
Evaluation
4.87
The observed traffic on the improved sections of the M25 is lower than the forecasts used for the
calculation of route stress in the appraisal, hence it can be concluded that route stress is better
than forecast, and on this measure, the route is rated as being uncongested. However, as pointed
out in the SAR, this is not a useful metric for this type of road.
4.88
As for the A2/A282, analysis of the reliability of journey times has been undertaken using the
proxy of the standard deviation of journey time data as above for the A2. Figure 4.3 and Figure
4.4 show the standard deviation of weekday journey times on the widened section of the M25.
4.89
Variation on the section J1b-2 has not been evaluated due to the low quality of the before period
data.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
67
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 4.3 – Standard Deviation of Journey Time on M25 J3 – 2 northbound
Figure 4.4 – Standard Deviation of Journey Time on M25 J2 – 3 southbound
4.90
The northbound carriage J3-2 clearly experienced the greater problems with variation of journey
times. After widening, the journeys in the AM peak have shown a big improvement in reliability.
Surprisingly the available data for the after period suggests some increased variation hence
unreliability during the inter-peak period whilst the PM peak from 17:00 onwards shows the
expected reliability improvements.
4.91
The southbound carriageway journey times were and are less unreliable. The standard deviation
showed an unexpected worsening during part of the AM peak whilst the early AM peak and PM
peak. Overall there is a small improvement in reliability for southbound journeys.
Wider Economic Impacts
Scheme Forecasts
A2/A282
4.92
The EAR (2003) for this scheme does not cover the wider economic impacts sub-objective.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
68
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
4.93
The AST states that the scheme would:
4.94
Improve access from M25 and A2 to regeneration areas in Kent. Vital for the future
development of Kent Thameside.
It was also assessed as serving a designated regeneration area.
M25 J1b - 3
Forecast Local impact
4.95
The Economic Impact Report (EIR) stated that the study area for the scheme included wards
featuring deprivation greater than the national average.
4.96
Improved road access was not considered to improve access to jobs for residents of the wards in
northern Dartford most in need of regeneration, since the people resident in these wards were
resistant to travelling long distances and did not have the means to acquire a car. Improved
public transport and additional job opportunities close to their homes were more important.
4.97
The scheme would increase the catchment area for employers in the study area located within
these wards. More reliable journey times on the M25 would increase the attractiveness of
committed development sites within or close to these wards.
4.98
The EIR estimated that up to 64 jobs could be realistically attributed to the scheme in 2008 rising
to a maximum of 303 jobs by 2018 (with 99 of these jobs being taken by local people from wards
in northern Dartford most in need of regeneration), once the benefits of the scheme and all the
committed development is complete.
Wider Impact
4.99
The SAR states that the M25 in this location is also critical to national competitiveness as it fulfils
the Regional Development Agency’s multi-criteria of being a piece of surface infrastructure of
national economic performance (SINEI) by providing access between the regions of London,
Southeast England and Eastern England, and access to various key ports and airports.
Combined Scheme Evaluation
4.100
The Communities and Local Government’s Indices of Deprivation 2004, ranks Dartford as 168th of
354 local authorities in England.
4.101
The details of the local developments upon which the specific forecasts for the M25 scheme were
based were not available at the time of this study. Also considering the impact of the recession it
was not considered too early to try to identify the job creation impact at this stage.
4.102
Kent Thameside is the regeneration area which covers the urban area north of the A2 in Dartford
and Gravesham borough. Through the improvements to infrastructure and observed beneficial
impacts on journey times and reliability, both schemes benefit the regeneration area.
4.103
The increase capacity and improved journey times is considered to be a benefit to the wider
impact of this part of the strategic road network on national competitiveness.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
69
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Key Points from Economic Section
Impact on Transport Economic Efficiency
 TEE was forecast to provide 99% of the benefits of these schemes;
 The evaluation of the outturn value of TEE based on observed savings in journey times one
year after opening for the turning movements at J2 and on the improved sections of the
mainline A2 and M25 shows savings of £170m (A2/A282 scheme) and £161m (M25) over
60 years; and
 These evaluations of the impacts to give outturn benefits are 14% below the overall benefits
forecast, but these are a conservative estimate of the benefits based only on a narrow
corridor whilst the forecast was based on detailed modelling of the impacts on not only the
strategic roads in the HA network but also the local authority roads within the wider Kent
Thameside Area. Therefore it can reasonably be assumed that the schemes have met or
exceeded the TEE benefit forecasts for the wider area.
Impact on Safety
 Safety benefits were forecast to be relatively minor but based on OYA observed savings
have been evaluated to be £37m which is 10% of the overall benefits, much higher than the
1% forecast;
 This evaluation of the outturn Safety benefits may be overestimated based on short term
benefits of reduced accidents in the post opening period from short term changes in driver
behaviour e.g. the following the removal of the roadworks but not all of the safety camera
notices.
Scheme costs and Benefit Cost Ratio
 The forecast scheme costs forecasts were accurate;
 The outturn benefit cost ratio is 2.2 which is very close to the forecast of 2.3 and shows that
the schemes represent good value for money.
Impact on Reliability
 Analysis of the variation in journey times shows a clear reduction in variability on the A2 and
hence there has been an improvement in reliability;
 On the M25, there is also a reduction in variation of journey times northbound, suggesting
an improvement in reliability.
Impact on Wider Economic Impacts
 The schemes have fulfilled their objectives in terms of putting in place the infrastructure to
improve road access to the regeneration areas of northern Kent and the Thames Gateway
area;
 At this stage of the post opening period and during a recession it is too early to identify job
creation in this area as a result of the highways schemes.
Future works not evaluated at this stage
 The impact of the Controlled Motorway scheme on M25 J2-3 becoming operational in the
near future is expected to have significant beneficial impacts on safety and to a lesser
extent on TEE.
 If the deferred link E part of the A2/A282 scheme is constructed in the future it is not likely to
change the overall profile of the findings of this evaluation.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
70
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5.
Environment
Introduction
5.1
This section evaluates the impacts of the scheme on the environmental sub-objectives of each
scheme.
5.2
The Environmental Statement (ES) for the M25 J1b-3 stated that the environmental objectives for
the scheme were:
5.3

To seek to minimise any increase in noise to adjacent property and achieve a reduction in
noise where reasonably practicable;

To minimise any deterioration in local air quality, particularly at local Air Quality Management
Areas (AQMAs) and achieve improvements in local air quality levels where reasonably
practicable;

To minimise adverse impact on landscape character and visual amenity, particularly on
locally designated landscapes and the Kent Downs Area of Outstanding Natural Beauty
(AONB), particularly in sensitive views; reinforce existing retained vegetation with on and
(subject to agreement) off-site planting;

To minimise adverse impact on the setting of listed buildings and conservation areas; to
avoid direct impact on archaeological remains, particularly in areas for site compounds and
storage;

To minimise direct loss of locally valuable habitats within the highway boundary, some of
which may also provide habitat for protected species; and

To minimise adverse impacts on water environment through use of enhanced pollution
control measures and adequate balancing storage.
The ES for the A2/A282 Dartford Improvement stated that the environmental objectives for the
scheme were:

To minimise the impact of traffic and of maintenance operations on watercourses,
groundwater and flooding;

To respect the landscape character and quality of an area when designing new roads or
improving existing roads. Seek to enhance the integration of the HA network into rural areas
using a combination of sensitive road alignment, earthworks, the use of appropriate materials
and planting to minimise the adverse effects of trunk road traffic on the countryside;

To manage the network in a practical way that promotes the maintenance and enhancement
of biodiversity (the variety of life). In particular, seek to manage the HA’s estate so as to add
to its existing value as a refuge and a linking feature for wildlife;

To ensure that in the planning and resourcing of trunk road projects there is an appropriate
response to any adverse effects on the historic environment and that the historic fabric of the
landscape is respected;

To take practical steps to minimise noise and disturbance. This includes providing
appropriate highway designs and making more use of noise reducing technologies;

To take practical steps to minimise emissions. This includes appropriate highway designs to
influence vehicle operation plus controls on the performance of contractors; and

To provide improved facilities along and across trunk roads and improve links to other key
destinations and to provide improved facilities for cyclists along and across trunk roads and
improve links to other key destinations.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
71
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5.4
The A2/A282 objectives are not scheme specific and are in line with the HA’s Environmental
Strategic Plan.
A2/A282 Dartford Improvement Link E Deferral
5.5
The ES for the A2/A282 was based on the approved scheme design at the time of the OPR. As
detailed earlier in 1.16, one of the planned new free-flow links included in as part of the junction
design the approved scheme, known as Link E was not constructed in the scheme completed
2007. The basis of the planned scheme used in the ES and January 2004 AST considered the
impacts of this link.
5.6
For the purposes of this study, the environmental impacts associated exclusively with Link E as
reported in the ES and the 2004 AST have been omitted. The impacts of the scheme without Link
E – as defined in the April 2006 Deferment Report and January 2008 AST Comparison – have
been assessed instead.
5.7
The key impacts avoided by the deferral of works to River Darent1 overbridges, is that the River
Darent is unaffected by the scheme, and construction of steepened embankments and retaining
walls at Hawley Manor have been avoided. Hawley Manor has instead been screened from the
existing A2 by a 2m environmental barrier (wooden fence).
Data Collection
5.8
The following documents have been used in the environmental evaluation part of this study:
M25 J1b-3

Appraisal Summary Table (AST), December 2006

M25 Junctions 1b to 3 Widening Scheme ES, November 2006: Volume 1A – main text;
Volume 1b – figures; Volume 3 – appendices; Non-Technical Summary.

Public Inquiry Landscape Proof of Evidence 2004

Handover Environmental Management Plan (HEMP), October 2008.

As Built drawings for drainage.
A2/A282
5.9

AST, January 2004.

AST Link E Deferral, June 2006.

A2/A282 Dartford Improvement ES, March 2003: Volume 1 – main text and appendices;
Volume 2 – figures.

A2/A282 Dartford Improvement Report on Deferment of Link E and Revised Landscape and
Drainage Attenuation Proposals in North West Quadrant of Junction 2, Issued at IFI, April
2006.

A2/A282 Dartford Improvement AST Comparison, Issued at IFI, January 2008.

HEMP, Issued at IFI, February 2008.

As Built drawings for drainage.
A full list of the background information requested and received to help with the compilation of this
reports is included in Table A.1 in the Appendix.
Site Inspections
5.10
A site inspection was undertaken on 25th and 26th February 2010 by an environmental specialist
and a member of the POPE team.
1
Note, the place names in this area spell the name of the village, wood and country park as Darenth while
the river and its valley are spelt Darent.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
72
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Consultations
5.11
Table 5.1 lists the organisations contacted regarding their views on the impacts they perceive the
road scheme has had on the environment, and whether they feel that the mitigation measures
implemented have been effective.
Table 5.1 – Summary of Environmental Consultation Responses
Organisation
Dartford Borough Council
Field of Interest
General
Comments
Noise: No evidence of changes in noise
level. Local residents, close to the M25
and A2 have informally mentioned that
the background traffic noise seems to be
lower.
No information
available.
Sevenoaks District Council
General
on
noise
complaints
No
emissions
data
available.
Recommended contact with Kent County
Council on rights of way and ecology.
Comments provided on visual impacts on
Swanley
Conservation
Area
and
surrounding environs.
Kent County Council
General
No response.
Environment Agency
Water
No data available on water impacts of the
scheme. However, it stated that if all
drainage and mitigation was implemented
as expected, the water environment
should have improved.
Natural England
Landscape and
Ecology
Declined to comment on impacts of
scheme but said that it expected a
detailed post-construction study to be
undertaken to monitor the effectiveness
of landscape and ecological mitigation.
English Heritage
Heritage
Declined to comment on either scheme.
Kent Wildlife Trust
Biodiversity
The Trust had been unable to undertake
any monitoring in relation to the scheme
and so cannot provide comment.
Kent Downs AONB Unit
Landscape and
Biodiversity
No specific comments on the impact of
either scheme provided.
However,
generic comment and advice on the
impacts of highways schemes and on
Kent Downs AONB was received.
Sutton-at-Hone and Hawley
Parish Council
General
POPE was raised at Parish Council
meeting but no further feedback received.
5.12
The Highways Agency Part 1 Team has been contacted regarding part 1 claims and it is
understood that it is too early in the claims period to say how many will be successful and this
information will be made available for the FYA report.
5.13
It should be noted that Part 1 Claims only cover permanent homes and not mobile homes, where
a different mechanism is in place. There is a caravan park adjacent to the A2 and claims made
for these homes should also be made available for the FYA report.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
73
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5.14
The MAC was also consulted with regard to animal mortality figures which have been made
available for the period May 2006 to March 2009. The MAC should be re-contacted for the FYA
report.
Traffic Forecasts and Evaluation
5.15
Three of the environmental sub-objectives (noise, local air quality and greenhouse gases) are
directly related to traffic flows. No new environmental surveys are undertaken for POPE and an
assumption is made that if the observed level of traffic is in line with forecasts then it is likely that
local noise and air quality are as expected. The baseline, forecast opening and design years for
each scheme are shown in Table 5.2.
Table 5.2 – Existing, Opening and Design Years for the M25 J1b-3 and A2/A282 Schemes
A2/A282
M25 J1b-3
Existing (Baseline)
2004
2002
Opening Year
2008
2007
Design Year
2023
2022
A2/A282
5.16
The traffic forecasts used in the noise and local air quality appraisals and the observed flows are
summarised in Table 5.3.
Table 5.3 – A2/A282 Traffic: Opening year Forecasts and Observed
Forecast1
Location
Low
Growth
High
Growth
Observed
Direction
WB
59,700
65,900
67,300
EB
58,800
65,500
67,000
WB
47,800
51,000
51,500
EB
46,900
51,400
56,700
Flyover from A282 to A2 eastbound
EB
16,000
16,900
16,600*
Flyover from A2 westbound to A282
northbound
NB
16,500
19,200
15,600*
Dedicated A2 eastbound to M25
southbound
SB
12,800
13,600
11,700*
M25 J2 -3
NB
71,900
81,900
64,700
M25 J2 -3
SB
69,400
78,600
70,600
NB
77,300
89,300
70,300*
SB
74,700
85,500
65,000*
A2 east of M25
A2 west of M25
M25 J1b-2 & A282 link road
*based on a single day video count
5.17
Table 5.3 shows the forecast used in the ES. These have the same basis as those discussed in
the traffic section of this report, which showed that traffic growth on the A2 increased in line with
the high growth forecasts whilst traffic on the M25 and movements at the junction have seen little
change. Because growth had been forecast on the M25 between the base year and the opening
1
2009 forecasts given in this table are based on the 2007 opening year forecasts in the ES growthed up using a straight line growth rate between 2007 and the design year forecasts. 5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
74
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
year, the observed traffic levels are, therefore, not as high as expected along the M25 and on the
A282 links.
M25 J1b-3
5.18
The ES used slightly differing types of traffic figures for the noise and air quality appraisal. Noise
was based on 18hour weekday figures (AAWT) whilst air quality used 24hour figures based on the
whole week (AADT).
Table 5.4 – M25 J1b-3 Traffic: Opening year Forecast and Observed AAWT (Noise)
18 hour AAWT
Location
Forecast
Observed
J1a-1b
174,200
140,800
J2-J3
160,900
137,500
Table 5.5 – M25 J1b-3 Traffic: Opening year Forecast and Observed AADT (Air Quality)
24 hour AADT
Location
5.19
Forecast
Observed
J1a-1b
184,000
143,700
South of J1b
156,000
138,500
J2-J3
170,001
140,300
J3-J4
136,000
115,200
Growth in traffic was predicted along the M25 but this has not been realised, possibly due to the
effects of recession. Present traffic levels are, therefore, well under those expected along the
M25.
Noise
Forecast
A2/A282
5.20
The AST for the A2/A282 Link E deferral stated that no properties would experience an increase
in noise levels in the Design Year and that 51 properties would experience a decrease in noise
levels of between 0.7 and 7.5 dB(A). 30 less people would be highly annoyed in the Design Year.
5.21
The ES for the A2/A282 stated that the following noise mitigation measures would be included in
the scheme design:
5.22

Low noise surfacing across the length of the scheme (however this would also be
implemented by Design Year with the Do Minimum scenario);

A 2m high barrier along the A2 at Hawley Manor; and

No properties would be eligible for noise insulation.
In the Design Year, with mitigation in place, the scheme was predicted to result in 51 properties
experiencing a significant decrease in noise in comparison to the 2002 baseline situation. Without
the scheme, 41 properties were predicted to experience a slight decrease in noise in the Design
Year in comparison to 2002.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
75
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
M25 J1b-3
5.23
The AST for the M25 J1b-3 stated that traffic flows on the scheme would increase slightly,
resulting in annoyance for properties nearby. However, the introduction of environmental barriers
at Hawley Road would result in an overall reduction in population annoyed by noise. In the Do
Minimum, 146 people would be subject to noise levels in excess of 69dBLA10,18hr, whereas with the
scheme, 108 would be exposed to this level of noise – a reduction of 38 people annoyed.
5.24
For the Do Minimum scenario, the AST estimated that 113 people were likely to be annoyed by
Design Year compared to 105 with the scheme – a net reduction of 8 people annoyed.
5.25
The ES for the M25 scheme stated that the following noise mitigation measures would be included
in the scheme design:

Low noise surfacing across the length of the scheme (however this would also be
implemented by Design Year with the Do Minimum scenario);

650m of environmental barriers along the M25 north and southbound carriageways at
Hawley; and

No properties would be eligible for noise insulation.
5.26
The greatest benefits for noise were predicted at Hawley, which was predicted to receive
substantial and moderate beneficial impacts, but noise impacts along the whole corridor are
generally predicted to fall due to the introduction of noise fencing and low noise surfacing.
5.27
Properties distant from the scheme, for example at Shirehall Road in Hawley were expected to
receive a marginal increase in noise in the design year as barriers are less effective at distance.
At Ship Lane, properties would also experience increases in noise at design year due to the
carriageway moving closer to properties. Such increases were not expected to be significant.
Consultation
5.28
Dartford Borough Council said it had no survey information to evidence any changes in noise level
due to either scheme. However, anecdotally local residents close to the M25 and A2 have
informally mentioned that the background traffic noise seems to be lower since the schemes were
operational. The Council does not record noise complaints and so have no data regarding
numbers of noise complaints before and after the schemes were implemented.
5.29
Sevenoaks District Council said it had no noise data available to comment on the noise impact.
Evaluation
5.30
For both schemes, the observed traffic flows differ from those predicted in the ES for the Do
Something scenarios, but are within 20% predictions. Therefore, it is likely that the impact of both
schemes on the local noise climate is generally as expected with regard to traffic flows. Low noise
surface has been used throughout the schemes as expected. It is understood that no post
opening noise surveys have been undertaken.
5.31
Much of the length of each scheme already lies within cutting prior to scheme construction and
thus had existing noise mitigation. Environmental barriers for noise mitigation have been
incorporated into the scheme at the locations identified in the ES.
5.32
Figure 5.1 to Figure 5.4 show environmental barriers across the M25 and A2/A282 schemes.
Along the M25 3m high, rather than 2m high environmental barriers have been implemented
following consultation on the ES. It is understood from the HEMP for the scheme that additional
barriers have been provided and although designed primarily for visual impact reasons, these
barriers also have a benefit to the noise environment.
5.33
Figure 5.1 and Figure 5.2 show the environmental barrier constructed at Hawley Manor. The
section of the A2 here was also resurfaced with low noise surfacing and was not affected by
widening or any of the new links provided at M25 J2.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
76
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.1 – 2m high environmental barrier (wooden fence) at Hawley Manor on the A2
Figure 5.2 – 2m high environmental barrier (wooden fence) at Hawley Manor on the A2
Figure 5.3 – 3m high environmental barriers (metal and wooden fencing) at Hawley (M25/ Dartford
Road underbridge)
Figure 5.4 – Environmental barriers (earth mounds) at edge of Links A and D at M25 J2
.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
77
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.5 – Additional environmental barrier near Pond 3
Figure 5.6 – Additional environmental barrier at M25/ Button Street underbridge
Table 5.6 – Summary of Noise Evaluation – A2/A282
Summary of Noise Impacts
Assessment
AST
(forecast)
No properties would experience an increase in noise
level in the Design Year (2022) due to use of low noise
surfacing, mounds and fencing. 51 properties would
experience a reduction greater than 3dB(A). Without the
scheme use of low noise surfacing in the Design Year
would mean 45 properties would experience a reduction
between 1 and 3 dB(A).
30 less people highly
annoyed in 2022
EST
Mitigation implemented as expected. The growth in
traffic predicted on the A2 has been slightly above
predicted but on the links around the junction and the
A282 traffic growth as has generally not materialised
(possibly due to recession factors discussed in the traffic
section of this report).
Likely to be as
expected at OYA
stage.
Origin of
Assessment
(OYA
evaluation)
However, traffic flows are generally as predicted and so
it is likely that the noise climate is as expected.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
78
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.7 – Summary of Noise Evaluation – M25 J1b-3
Summary of Noise Impacts
Assessment
AST
(forecast)
Traffic flows on the scheme would increase slightly,
resulting in an increase in annoyance for properties
nearby. However, the introduction of environmental
barriers at Hawley Road result in an overall reduction in
population annoyed. Parkwood Hall School is more than
400m from the proposed alignment. It is not close
enough to the scheme for the noise change to have an
effect on overall noise levels in excess of 69dBLA10,18hr
whereas with the scheme 108 would be exposed to
noise levels in excess of 69dBLA10,18hr. This is a
reduction of 38 people.
Net reduction in
estimated population
annoyed: 8
EST
More mitigation implements than expected (additional
and higher fencing across M25 corridor). The rate of
growth in traffic predicted on the M25 for the opening
year has not materialised (possibly due to recession
factors discussed in the traffic section of this report) and
implementation of additional mitigation compared to that
expected may mean a reduction in noise compared to
expectations.
Probably better than
expected at OYA
stage.
Origin of
Assessment
(OYA
evaluation)
Local Air Quality
Forecast
A2/A282
5.34
The AST stated that local air quality was poor, particularly in close proximity to the A2 and A282.
‘Cleaner’ vehicles in the future were likely to contribute to an improvement in local air quality with
or without the scheme, but there would be less of an improvement with the scheme compared to
the Do Minimum scenario.
5.35
An Air Quality Management Area (AQMA) was present within Dartford Borough which could be
affected by the scheme. However, the ES showed that the effect on air quality at properties within
the AQMA would not be discernable. Properties near the Littledale Viaduct would generally have
an increase in concentrations, while those near the Bean Junction would generally have a
decrease in concentrations.
5.36
The scheme was noted as having a slight negative effect on local air quality in comparison to the
Do Minimum with eight of the ten receptors expected to have an increase in concentrations.
5.37
The ES noted that National Air Quality Standards would be exceeded for both NO2 and PM10 in
the base year, although these were likely to be met in the opening and design years.
5.38
Of 91 properties within 200 metres of the Scheme, 27 properties were predicted to experience
better air quality as a result of the scheme and 64 properties were predicted to experience a
marginal deterioration in air quality. In general terms, properties predicted to experience
improvements in air quality were located around Bean Junction and those expected to experience
poorer air quality were located in the vicinity of the Littledale Viaduct and locations where
elements of the Scheme, such as new slip roads, would bring the road closer to the properties.
M25 J1b-3
5.39
The AST stated that traffic flows would increase slightly and properties adjacent to the M25
between J1b and 2 within Dartford Borough Council’s AQMA could experience a slight
improvement in air quality due to speed changes. It is presumed that this referred to the impact of
reduced congestion at the junction. Properties south of Junction 2, some of which were within
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
79
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Sevenoaks District Council’s AQMA were expected to experience no discernable change in air
quality.
5.40
AQMAs are present within Dartford Borough Council and Sevenoaks District Council and could be
affected by the scheme. However, the ES predicted that no AQMAs would experience
deterioration in air quality because of the scheme.
5.41
176 properties lie within 200m of the scheme and of these, 63 were predicted to experience an
improvement in air quality. These improvements were associated with J1b - 2 which was widened
on the southbound carriageway only. The remainder of properties were predicted to experience a
decrease in air quality.
5.42
2010 annual mean EU Value Limits for nitrogen dioxide (NO2) were predicted to be exceeded both
with and without the scheme at 8 out of 19 receptors in the opening year (2008) and at 6 out of the
19 receptors by 2010, both with and without the scheme.
Consultation
5.43
Sevenoaks District Council said it did not have any data on local air quality.
Evaluation
5.44
Traffic on the A2, M25 and the A282 links vary above and below the high and low growth
forecasts, mainly below. The biggest difference is on the A2 eastbound which is 10% above the
high growth forecast.
5.45
As all observed traffic flows are within 10% of either the high or low forecast levels and many are
below forecast, it is possible, therefore, that scheme impacts for both schemes are better than
expected at OYA stage. It is likely that, as expected, neither of the AQMAs in Dartford BC or
Sevenoaks DC have suffered a deterioration in local air quality.
Table 5.8 – Summary of Air Quality Evaluation – A2/A282
Origin of
Assessment
AST
(forecast)
Summary of Local Air Quality Impacts
Local air quality is poor particularly in close proximity to
the A2 and A282. ‘Cleaner’ vehicles in the future are
likely to contribute to an improvement in air quality.
Nevertheless anticipated improvement overall would be
less with the Scheme when compared to Do Minimum
Scenario.
Assessment
Weighted property
concentrations
(opening
year):
PM10 +1780.2_g/m3
NO2 +2344.60_g/m3
EST
(OYA
evaluation)
All observed traffic flows are within 10% of either the
high or low forecast levels. Therefore, it is likely that the
air quality on the A2/A282 is as expected.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
Likely to be as
expected
80
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.9 – Summary of Air Quality Evaluation – M25 J1b-3
Summary of Local Air Quality Impacts
Origin of
Assessment
AST
(forecast)
EST
(OYA
evaluation)
Traffic flows would increase slightly. Properties adjacent
to the section of M25 between J1b and 2 before slip
roads show very slight improvements in air quality due to
speed changes. This area is within Dartford BC’s
AQMA. Properties adjacent to the section of M25 before
J2 slip roads and J3 show no discernable change in air
quality. Some of these properties fall within Sevenoaks
DC’s declared AQMA.
The level of growth in traffic predicted on the M25 has
not materialised (possibly due to recession factors
discussed in the traffic section of this report). Observed
traffic across the M25 is at least 10% less than
expected, meaning that air quality is likely to be better
than expected. As expected it is likely that there has
been no worsening in air quality within local AQMAs.
Assessment
Weighted property
concentrations
(opening
year):
PM10 +209.73_g/m3
NO2 +126.65_g/m3
Likely to be better
than expected.
Greenhouse gases
5.46
According to the DfT’s WebTAG guidance, CO2 is considered to be the most important
greenhouse gas and, therefore, is been used as the key indicator for the purposes of assessing
the impacts of transport options on climate change.
5.47
The ESs and ASTs for each scheme included assessments of the CO2 impact. Although the
focus is on CO2 emissions, the current guidelines are to express the change in terms of the
change in the equivalent tonnes of carbon released as a result of implementing a transport
scheme. Therefore the original forecasts figures have been converted to tonnes carbon for the
purpose of this evaluation.
Forecast
A2/A282
5.48
5.49
5.50
The greenhouse gas impact of the scheme was assessed using the guidance for regional air
quality modelling from the DMRB. This models fuel consumption related carbon emission rates
and requires the following basic inputs:

Annual average daily traffic flow to include heavy good vehicles (HGVs) and light duty
vehicles (LDVs);

Percentage of HGVs on each road;

Average speed of vehicles; and

Assessment year.
Paragraph 3.2.6.1 of the ES stated:
The detailed modelling of complex major junctions is not included within the prediction
methodology as it relies on average speeds, traffic composition and road lengths. However,
improvements at the A2/A282 junction are likely to result in reduced congestion which
results in reduced CO2 emissions at higher speeds. Therefore the increase in greenhouse
gases is likely to be overstated. Detailed modelling of major junctions is not part of this
assessment.
The published forecast was 5,187 additional CO2 impact of 2022. No data was given for the
opening year. This is equivalent to 1,415 tonnes carbon.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
81
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5.51
The assessment in the Link E deferral report stated that the revised layout would not affect the
greenhouse gases assessment. This was because traffic which was previously forecast to have
used Link E will now flow onto a temporary Link located on the existing roundabout, which does
not result in traffic flow changes to any other road links.
M25
5.52
The greenhouse gas impact of the scheme was also assessed using the DMRB air quality
spreadsheet. The forecast was a net impact of 3,390 CO2 impact in the opening year of 2008,
equivalent to 925 tonnes carbon. This was a net increase of 4% between the Do Minimum and
Do Something scenarios.
Evaluation
A2/A282
5.53
As described above, the appraisal did not consider the junction; hence the evaluation here has
also been based only on the mainline traffic on the widened section of the A2.
M25 J1b - 3
5.54
The area covered by the appraisal was not known. The evaluation has been based on flows and
speeds in the AM, IP and peak periods for the section J2-3 for the situation before and after the
scheme was implemented. The improved section of J1b – 2 cannot be evaluated due to
insufficient data of the necessary granularity.
Table 5.10 – Summary of Greenhouse Gases Evaluation – A2/A282
Origin of
Assessment
Summary of Greenhouse Gases Impacts
Assessment
AST
(forecast)
Increase due to increased traffic flows, but likely to be
overstated due to impact on junction congestion
1,415 tonnes
carbon, a 9.5%
increase (in design
year 2022)
EST
Increased emissions due to traffic growth above forecast
1,349 tonnes
carbon, 11%
increase (2009)
(OYA
evaluation)
Table 5.11 – Summary of Greenhouse Gases Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Greenhouse Gases Impacts
Assessment
AST
(forecast)
Increased emissions due to increased traffic
924 tonnes carbon,
4% increase with
scheme (2008)
EST
Increased emissions due to increased speeds
724 tonnes carbon,
4% increase with
scheme
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
82
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Landscape and Townscape
Forecast
A2/A282
5.55
The AST for the A2/A282 predicts that the scheme would have a slight adverse impact on
landscape due to degradation of the urban fringe landscape. The existing motorway/ link road/
junction would be screened by mounding and planting but the fourth tier of the new junction works
at M25 J2 would remain visible after mitigation.
5.56
Townscape has not been appraised for the A2/A282 scheme due to the lack of townscape
features in the vicinity of the scheme.
5.57
The ES described impacts of the scheme as incremental on a landscape described as ‘urban
fringe’, rather than introducing new features to a landscape already dominated by road
infrastructure. New link roads would have new lighting, whilst the existing A2 and A282 lighting
would be replaced with lighting of the same standard as the link roads, in the central reservation.
This modern lighting should reduce light spillage. Gantries would be also be included and
locations are noted on Figure 5 Volume 2 of the ES. The Landscape Proof of Evidence also notes
that both lighting and overhead gantries were taken into consideration in the visual appraisal for
the scheme, although the ES Volume 1 text would appear to make no reference to gantries. The
impacts to the landscape character of the area were considered to be moderate at opening year in
the areas northeast and northwest of M25 J2 and the Littledale Viaduct (A2). The affected
landscape includes the Darenth Country Park, Fleet Downs and Blackdale Farmland.
5.58
Other landscape impacts to the south west of J2 towards Hawley, and to the east of the Littledale
Viaduct, through Darenth Wood Site of Special Scientific Interest (SSSI) towards Bean, were
considered to be slight at opening, reducing to neutral at design year.
5.59
Key visual impacts for the scheme would generally be in the vicinity of the Littledale Viaduct and
M25 J2. Blackdale Farm Cottages and residential properties on Green Street, Green Road
including Littledale and Gore Cottages, all near M25 J2, were predicted to experience a
substantial adverse impact in the opening year, reducing to moderate in the design year.
5.60
Properties on the edge of Dartford would also experience a slight/moderate impact at opening
year, reducing to slight impact in the design year, due to views of M25 J2.
5.61
The Northern edge of Hawley was predicted to experience a moderate adverse visual impact at
opening, reducing to slight impact at design year, also due to views of J2.
5.62
Hope Cottages near the Bean Interchange were predicted to receive a slight visual impact in
opening year.
5.63
A number of public rights of way within the vicinity of the scheme would also receive substantial
and moderate visual impacts.
5.64
The elements of design proposed to mitigate landscape impacts were:

Protection and management of existing retained highway vegetation;

Reinforced planting to existing retained highway vegetation;

Woodland planting on newly constructed earthworks;

Woodland planting on land beyond that required for highway earthworks, but acquired for the
purposes of essential landscape mitigation;

All planting to be native and stock of UK provenance wherever possible;

Creation of wildflower grassland;

Creation of low-lying wetland areas;

Creation of balancing ponds/ ditches/ reed beds;
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
83
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Provision of visual and noise attenuation mounding above new/ existing carriageway;

Regrading of embankments; and

The return of some of the re-graded land back to agricultural use.
M25 J1b-3
5.65
The AST for the M25 scheme predicted a slight adverse impact overall. The AST noted a Special
Landscape Area and two Areas of Local Landscape Importance (ALLI) in the study area, although
the scheme was predicted not to detract from or be in conflict with the area’s existing features and
landscape character. Tranquillity and land cover were predicted to be slightly affected by the
scheme and proposed lighting would add to the impact with a change in night time landscape
character from several visual receptors. Effects of lighting on the Kent Downs Area of
Outstanding Natural Beauty (AONB) would be slight due to the existing lighting at J3.
5.66
The AST predicted the impact on townscape to be neutral as the increased dominance of the M25
on views would be offset by new environmental barriers; particularly at Hawley. Adverse impacts
were not expected to the Conservation Area at Swanley Village.
5.67
The ES noted that the landscape around J2 would be dominated by the junction improvement
associated with the A2/A282 project and the impacts of improving the M25 to the north of this
junction would be overridden by these impacts, although the Blackdale Farmland landscape
character area would receive slight adverse impacts at opening due to new gantries. The ES also
predicted slight adverse landscape impacts at opening for the Darent River Valley, Hawley
Downs, Swanley and Broom Hill Fringe and Sutton at Hone Downs local landscape character
areas. Because of its proximity to the scheme a small area of the Kent Downs AONB directly
adjacent to J3, mostly occupied by a golf course, would suffer a localised slight adverse night time
impact due to the proposed lighting north of J3. The ES noted that the character of the Kent
Downs AONB would remain largely unaffected.
5.68
The ES noted that the M25 was already lit between J1b and J2 and unlit between J2 and J3.The
scheme proposals were to upgrade existing lighting through J2 and to introduce new lighting from
J2 to just north of J3. The lighting would be located in the central reserve north of Yew Tree
footbridge and in the verges south of Yew Tree footbridge.
5.69
Farningham and Rams Woodland character area would experience a moderate adverse impact
both at opening and design year, largely due to removal of screening vegetation adjacent to the
M25 and due to the effects of the proposed lighting on night time character, and the increased
dominance of the motorway on a rural landscape and landscape features of moderate quality.
Farningham Wood is also designated as an SSSI.
5.70
The only properties predicted to experience substantial and moderate adverse visual impacts
were at Hawley and Blackdale Farm Cottages, although the impacts at the Farm Cottages would
be overridden by the impact of the J2 improvement undertaken under the A2/A282 scheme.
Impacts were predicted largely due to removal of screening vegetation and the close proximity of
the properties to the widened M25.
5.71
A number of public rights of way within the vicinity of the scheme would also receive substantial
and moderate visual impacts reducing to slight by the summer of the design year due to mitigation
screen vegetation maturing.
5.72
The elements of design proposed to mitigate landscape impacts were:

Protection and management of existing retained highway vegetation;

Reinforced planting to existing retained highway vegetation;

Replacement planting for existing highway vegetation that is lost to the scheme;

All planting to be native and stock of UK provenance wherever possible;

Creation of wildflower grassland; and
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
84
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Installation of environmental barriers at Hawley Road underbridge.
Consultation
5.73
Sevenoaks District Council stated that the large gantries have an adverse impact on the rural
setting of Swanley Village Conservation Area. It also noted that due to the paucity of screening to
the eastern side of the M25 in the area of the village, moving vehicles dominate long-views of the
village from the east.
5.74
Kent Downs AONB stated that it was unable to make specific comments on the impacts of the
scheme on the AONB at this stage.
Evaluation
5.75
The site visit confirmed that mitigation had largely been implemented as expected. Environmental
barriers were installed at Hawley (Figure 5.3) and Hawley Manor (Figure 5.1 and Figure 5.2) as
expected, but the height of the barriers along the M25 were increased from 2m – as described in
the ES – to 3m after consultation on the ES. They were also extended along a further distance to
reduce the visual impact of the widened scheme, as demonstrated in Figure 5.5 and Figure 5.6.
5.76
Reinforcement planting (Figure 5.2) and new planting (Figure 5.7) was evident throughout the
schemes and vegetation was retained where expected. Planting has been individually guarded
with shelters, as shown in Figure 5.7.
Figure 5.7 – View southbound along A282 towards M25 J2 showing new planting with individual
shelters
5.77
As compensation for land lost to the scheme at Darenth Country Park, it is to be exchanged with
land behind Gore Farm Cottages (as described in the ES), although it is understood that this has
not yet been completed. This transfer should be confirmed as part of the FYA evaluation.
5.78
Due to the time of year it was not possible to confirm whether wildflower grassland had been
implemented, although the HEMPs for both schemes note that grassland seeding had been
undertaken and that wildflower areas are present at the lower sections of some embankments.
The HEMP also confirmed that land to be returned to agriculture post construction had been
seeded and this was evident on the site visit.
5.79
Further details on vegetation retention and translocation can be found in the ecology section.
Creation of wetlands is also covered in the ecology and water sections.
5.80
Landscape effects and visual impacts were generally as expected at OYA stage. Implementation
of barriers at Hawley and Hawley Manor have screened the A2 and widened M25 from visual
receptors. New and reinforced planting has been implemented across both schemes were
expected and, subject to ongoing maintenance and management, should established satisfactorily
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
85
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
and, given time, reduce visual and landscape impacts. Establishment of the landscape measures
should be considered at the five years after stage.
5.81
The townscape impacts on Hawley are also as expected at OYA. Barriers (see Figure 5.3) and
planting have been implemented as expected, screening Hawley from the M25. New gantries are
visible from the town, but this is offset by the new environmental barriers which reduce the visual
and noise impacts of traffic.
5.82
Sevenoaks District Council commented that long views from the east of the M25 have been
changed due to installation of gantries. Gantries are also visible from the rural land situated
around the Conservation Area. The ES clearly stated that gantries would form part of the scheme
proposals and also indicated that the Conservation Area is outside the scheme’s visual envelope.
During the site visit, it was not evident that the scheme was visible from within the Conservation
Area itself. Therefore it is not considered that the scheme impacts on it.
5.83
Visual impacts at Blackdale Farm Cottages are considered to be substantially adverse as
expected, and, again, new planting has been implemented to soften the impact of the
embankment. Figure 5.8 shows a view of the scheme from this location.
Figure 5.8 – View of M25 J2 Link A from Blackdale Farm Cottages
5.84
Views from the edge of Dartford at the northern edge of Darenth Country Park are also considered
to be as expected. The Year 1 photomontage in Figure 25 of the A2/A282 ES Figure 5.9 is an
accurate representation of the actual view taken on site (Figure 5.10).
5.85
Visual impacts from properties near to the Littledale Viaduct (A2) were also predicted to be
substantially adverse due to the addition of raised carriageways on either side of the existing A2
viaduct. The new viaducts were finished, as proposed, in weathered steel.
5.86
Figure 5.12 recreates the proposed view shown in the photomontage in Figure 26 of the A2/A282
ES and demonstrates that the predicted visual impacts are as expected.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
86
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.9 – Figure 25 Proposed View Year 1 photomontage from the A2/A282 ES (2003). View towards M25 J2 from Darenth Country Park, taken during summer.
Figure 5.10 – Recreation of photomontage from Figure 25 of the A2/A282 ES. View towards M25 J2 from Darenth Country Park, taken February 2010.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
87
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.11 – Figure 26 Proposed View photomontage from the A2/A282 ES (2003). View towards M25 J2 from Darenth Country Park, taken during summer.
Figure 5.12 – Recreation of photomontage from Figure 26 of the A2/A282 ES. View towards Littledale Viaduct (A2) from Gore Farm Cottages, taken February 2010.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
88
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
5.87
Impacts of scheme lighting are also largely as expected, such as at Farningham and
Rams Woodland. However, the effect of lighting Kent Downs AONB may be considered
to be negligible due the already lit nature of M25 J3 and other development skirting the
edge of the designation. The AONB was unable to make any specific comments on the
impacts of the scheme. Lighting is visible from other receptors along the M25 corridor,
but increased length of 3m high environmental barriers (wooden fences) has reduced the
impacts of the headlights of vehicles using the M25.
Table 5.12 – Summary of Landscape Evaluation – A2/A282
Origin of
Assessment
Summary of Landscape Impacts
Assessment
AST
(forecast)
Degraded urban fringe landscape, existing motorway/
link road/ junction screened by mounding and planting.
Fourth tier to J2 visible.
Slight adverse
EST
Mitigation generally implemented as expected but it is
too soon to evaluate the success of the new landscape
planting in screening traffic and integration of the
scheme into the local landscape. Further study required
at FYA. Landscape effects and visual impacts as
expected at OYA.
As expected
(OYA
evaluation)
Table 5.13 – Summary of Landscape Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Landscape Impacts
Assessment
AST
(forecast)
1 Special Landscape Area and 2 ALLIs in Study Area.
Scheme would not detract or be in conflict with existing
features and landscape character of the area, although
tranquillity and land cover across the area would be
slightly affected. Proposed lighting would add to impact,
with a change in night time landscape character from
several visual receptors. Effects on lighting on the Kent
Downs AONB would be slight as currently lit J3
intervenes.
Slight adverse
EST
Mitigation generally implemented as expected but it is
too soon to evaluate the success of the new landscape
planting in screening and integration. Further study
required at FYA. Additional height (3m rather than 2m
high) environmental barriers provided along a greater
length of the M25 may have reduced effect of headlights
at night.
Impact on landscape designations as
expected. Kent Downs AONB should be consulted
again at FYA stage. Landscape effects and visual
impacts as expected at OYA.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
89
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.14 – Summary of Townscape Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Townscape Impacts
Assessment
AST
(forecast)
Although the scheme would impact upon housing at
Hawley, in terms of views and increasing the dominance
of major roads in the area, adverse impacts would be
offset with installation of environmental barriers.
Neutral
EST
Limited townscape character within scheme area.
Mitigation generally implemented as expected. Although
new gantries are visible from Hawley, the new
environmental barriers have offset the impacts of the
M25.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
90
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Cultural Heritage and Archaeology
Forecast
A2/A282
5.88
The AST predicted impacts on regionally important archaeological remains and on the
settings of Listed Buildings and Scheduled Monuments. A moderate adverse impact was
predicted.
5.89
However, the ES predicted only slight adverse impacts on cultural heritage and
archaeology. Once the link E deferral was taken into account, this impact was considered
to be neutral on the settings of designated heritage assets due to screening of Listed
Buildings and a Scheduled Monument at Hawley Manor.
5.90
The ES noted that the A2 had already severed a Scheduled Monument at Darenth Wood
– a medieval earth boundary, but this would not be affected by the scheme.
5.91
Impacts were predicted to known sites of buried archaeology within the footprint of the
scheme (see Table 5.15)
5.92
Other cultural heritage assets within the vicinity of the scheme would not be affected.
5.93
Mitigation proposals comprised:

Targeted fieldwork and watching brief. Archaeology report to be published.

Environmental barrier at Hawley Manor (although no additional impacts were
predicted from the A2 adjacent to Hawley Manor as a result of the scheme).
M25 J1b-3
5.94
The AST predicted slight adverse impacts to regionally important archaeology, but these
would be limited due to restricted width of land-take.
5.95
The ES predicted negligible impacts to Grade II Listed Buildings around Darenth. These
comprise a listed wall at Sutton Place and Mill House, Chequers Inn and Ivy Cottage on
Darenth Road, which have a distant view of the scheme.
5.96
Swanley Conservation Area and associated Listed Buildings would not be affected by the
scheme. It is not possible to see the scheme from this location.
5.97
Impacts were predicted to known sites of buried archaeology within the footprint of the
scheme (see Table 5.16).
5.98
Mitigation proposals comprised:

Consultation with Kent County Council;

Targeted fieldwork and watching brief; and

Archaeology report to be published.
Consultation
5.99
English Heritage was consulted but responded that its involvement with either scheme
was minimal.
Evaluation
5.100
Impacts are generally considered to be as expected. The only designated buildings to be
affected by the schemes were the Listed Buildings and Scheduled Monument at Hawley
Manor. The setting to these buildings was affected due to construction of a 2m high
environmental barrier. This barrier introduced a new feature to the area, and now
provides screening against the existing A2 (see Figure 5.13). This was noted in the
Deferral Report as being a neutral impact but in fact there is a slight to moderately
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
91
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
positive impact on Hawley Manor as traffic is no longer visible from the site and noise
impacts would have also been reduced.
Figure 5.13 – Scheduled Monument and Listed Buildings at Hawley Manor with screening
environmental barrier
5.101
Swanley Conservation Area and the Listed Buildings located there remain unaffected by
the scheme, as predicted (further comment is provided in the landscape sub-section).
The settings of the Listed Buildings around Darenth have received negligible impacts, as
expected; although the M25 and new gantries are visible from these buildings, due to the
distance from the scheme, these impacts only have a negligible impact on the settings of
the buildings, which were already in view of the pre-existing M25. Figure 5.14 shows the
Listed Building (wall) at Sutton Place illustrating a new M25 gantry visible in the middle of
the photograph.
Figure 5.14 – Listed Building (wall) at Sutton Place with new gantry in distant view
5.102
The Scheduled Monument at Darenth Wood – a medieval earth boundary – passes close
to the A2 widening but remains unaffected by the scheme. It was formerly severed by the
pre-existing A2.
5.103
At the time of writing no archaeological information has been provided to POPE and this
should be considered as part of the five years after study. The archaeology report,
produced by Oxford Archaeology has not yet been completed but is due during 2010.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
92
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.15 – Summary of Heritage Evaluation – A2/A282
Origin of
Assessment
Summary of Heritage Impacts
Assessment
AST
(forecast)
Deterioration to setting of Listed Buildings and
Scheduled Monument and impact on regionally and
locally important archaeological remains.
Moderate adverse
EST
Based on effects on settings to Scheduled Monuments
and Listed Buildings, impacts are better than expected in
the AST due to improvements at Hawley Manor. The
ES reports only slight adverse impacts to buried
archaeology and the setting of Hawley Manor (an impact
not realised due to the deferral of Link E).
As expected
(OYA
evaluation)
Table 5.16 – Summary of Heritage Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Heritage Impacts
Assessment
AST
(forecast)
The scheme will have a negative impact on regionally
important sites, but the actual extent of the impact is
limited because of the width of the land-take.
Slight adverse
EST
Impacts to settings of cultural heritage assets such as
Listed Buildings and Swanley Conservation Area are
considered to be minimal and as expected.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
93
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.17 – Summary of predicted heritage and archaeology effects, proposed mitigation and evaluation of impacts
Cultural Heritage Features
Hawley Manor
Grade II and II* Listed Buildings
Proposed Mitigation
Evaluation
Original mitigation as stated in ES not required due to Link E deferral. Deferral
Report proposes a 2m high barrier to provide screening from existing A2.
2m high environmental barrier constructed at Hawley Manor and
reinforced planting undertaken. Barrier provides screening from
A2. Impact is neutral as expected in Deferral Report – actual
impact is positive due to screening of traffic.
Targeted programme of archaeological fieldwork, including publication.
The HEMP states that a site-wide watching brief was carried out
in risk areas.
Dovecote at Hawley Manor
Scheduled Monument
Later prehistoric and Roman sites possibly
disturbed by A2/A282 earthworks:
 Site of 14 pits and 7 post holes of a Bronze
A combined archaeology report for both schemes by Oxford
Archaeology is due later in 2010 and should be made available
to POPE for the FYA report.
Age to Iron Age Pottery and flint finds.
 Site of late prehistoric/early Roman(?)
settlement including19 Roman ovens/kilns
and 9 possibly prehistoric pits.
 2 concentrations of possible pits and cut
features
may
represent
settlement/activity.
prehistoric
 Possible
plough-levelled lynchets/field
system perhaps associated with site of
Roman kilns (above).
Known sites of buried archaeology that may be
affected by M25 earthworks (unknown
condition):
 Find site of Palaeolithic hand axes adjacent
Targeted programme of archaeological fieldwork to be confirmed with Kent County
Council Heritage Conservation Group, including publication.
The HEMP states that a site-wide watching brief was carried out
in risk areas.
Trial trenching to bar carried out at foot of treatment pond where there is a high risk
of uncovering archaeological remains.
A combined archaeology report for both schemes by Oxford
Archaeology is due later in 2010 and should be made available
to POPE for the FYA report.
to Swanley.
 Mesolithic find at M25 J3 from possible
lithic work site.
 Iron Age Farmstead near Sutton at Hone
and Hawley.
 Iron Age settlement.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
94
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Biodiversity
Forecast
A2/A282
5.104
The AST stated that there would be no direct impact to Darenth Wood SSSI but there would be
impacts to calcareous grassland, dormice and reptiles. Overall impacts were predicted to be
slight adverse.
5.105
The ES predicted that there would be no direct loss of land from any designated sites. The A2
already ran through Darenth Wood SSSI and some loss of vegetation would occur along the edge,
removing screening between the A2 and the SSSI. This would also have impacts upon dormice,
which were known to be present in the area.
5.106
Other impacts on species included wood ants. A number of colonies would be lost by the
widening of the road. This would be mitigated by translocation of colonies to the edge of the
SSSI.
5.107
Calcareous grassland would also be lost along this length of the A2, but it was proposed that this
should be transplanted to a pre-prepared site within Darenth Country Park.
5.108
Another scarce species of plant, dittander, would also be transplanted from a soakaway to be
removed as part of the scheme, to a suitable wetland location.
M25 J1b-3
5.109
The AST predicted that there would be no impacts to designated sites but there would be loss of
habitat for reptiles and breeding birds, which would be enhanced through appropriate mitigation.
Overall impacts were predicted to be slight adverse.
5.110
The ES stated that the impacts of the scheme would be limited due to the small amount of landtake required. It was predicted that there would be no direct loss to any designated sites,
although there would be loss of screening planting at the edge of Rams Wood East and West,
which is an ancient woodland.
5.111
Potential operational impacts on Sutton-at-Hone Lakes SNCI (Site of Nature Conservation
Interest) would be avoided due to the scheme allowing no direct discharge to the River Darenth.
New drainage and pollution mitigation systems would be implemented to prevent pollution to the
river (discussed in the water and drainage section).
5.112
Impacts to protected species included loss of habitat for reptiles and loss of bird breeding territory
within verges where vegetation would be removed.
Consultation
5.113
Natural England declined to comment on the impacts of the scheme but said it expected detailed
monitoring of landscape and biodiversity scheme mitigation to be undertaken.
Evaluation
5.114
Impacts of the scheme are generally as expected, although sufficient information on ongoing
mitigation has not yet been made available to POPE and should be provided at FYA stage.
During the site visit it was possible to see that some of the mitigation proposed by the ES had
been implemented.
5.115
Impacts at Darenth Wood SSSI were largely as expected and there was no material loss to the
designated woodland. Additional planting has been provided along the verge at the edge of the
A2 although this is not yet mature (see Figure 5.15). Personal communication with the Managing
Agent also confirmed that dormouse mitigation had been implemented within the woodland and
that ongoing monitoring was being undertaken.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
95
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.15 – Planting at edge of Darenth Wood SSSI
5.116
New drainage and pollution mitigation has been implemented as expected for both schemes and it
is therefore assumed that the impacts of the scheme on the sensitive aquatic habitats, including
Sutton-at-Hone Lakes SNCI are as predicted. POPE has not been made aware of any
information suggesting that there have been further impacts to aquatic habitats.
5.117
As stipulated in the ES, the dittander was transplanted to a new location (as confirmed by the
Managing Agent), although details on the success of this relocation are not yet known to POPE.
The calcareous grassland was also transplanted, as expected, to Darenth Country Park. Details
on the success of this relocation are not yet known to POPE. Monitoring details for dittander and
calcareous grassland are not yet available and will be made available to POPE for inclusion in the
FYA.
5.118
Impacts to Rams Wood East seemed at the time of the site visit to be less than expected.
Screening vegetation along the M25 embankment next to the wood was not lost, as predicted in
the ES, and replanting was therefore not required. Figure 5.16 shows Rams Wood, to the right of
the photograph, and the adjacent M25 embankment, which remains thickly wooded.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
96
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Figure 5.16 – Ancient Woodland at Rams Wood East
5.119
Verges and embankments lost to reptiles at construction phase have been replaced with new
areas of embankment, replacing lost habitat, as expected. Details of post-construction reptile
surveys have not been made available to POPE for this OYA report but should be available at
FYA stage.
5.120
Biodiversity should be considered at the FYA stage when further monitoring information may be
available.
Table 5.18 – Summary of Ecology Evaluation – A2/A282
Origin of
Assessment
Summary of Biodiversity Impacts
Assessment
AST
(forecast)
No direct impact to any designated sites but indirect impact
on Darenth Wood SSSI. Direct impacts on calcareous
grassland, dormouse habitats and reptiles.
Slight adverse
EST
Mitigation seems to have been implemented as expected and
impacts to Darenth Wood SSSI are as expected. Calcareous
grassland was relocated to Darenth Country Park and
dittander was relocated to a new watercourse. Further
information on success of relocation should be made
available at FYA stage. Impacts to protected species appear
to have been adequately mitigated. New embankments have
provided replacement habitat for reptiles and management of
SSSI has been undertaken to encourage dormice. Wood
ants relocation was successful and local populations
threatened by the scheme have been safeguarded (see
Table 5.20).
As expected
(OYA
evaluation)
Table 5.19 – Summary of Ecology Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Biodiversity Impacts
Assessment
AST
(forecast)
No impact on designated sites. The reduction in the width of
the soft estate as a result of widening would contribute to a
loss of habitat for reptiles and breeding birds. However, the
biodiversity of the retained habitats would be enhanced
through appropriate mitigation.
Slight adverse
EST
No impact on designated sites, as predicted, and mitigation
largely implemented as predicted although planting has not
yet matured. Lost habitat for reptiles has generally been
replaced due to new verges created along the J2
improvements as part of the A2/A282 scheme.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
97
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.20 – Ecology potential impacts, mitigation and evaluation of impacts
Designated Sites
Aspect
Predicted Impact
Mitigation Measures
Evaluation
Loss of vegetation and grassland at A2
carriageway edge adjacent to Darenth Wood
SSSI.
Replanting to be undertaken in the verge at
Darenth Wood.
Replanting has been undertaken along the verge next to Darenth
Wood but has not yet matured. Impact on Darenth wood as
expected.
Sutton-at-Hone Lakes SNCI downstream of M25
widening scheme along River Darent. Potential
surface water pollution.
No run-off to be discharged directly to River Darent
from either scheme. All run-off to be collected and
carried to attenuation ponds via pollution control
infrastructure.
Nationally scarce plant – Dittander – normally
associated with salt marsh habitat found in
soakaway at Blackdale Farm to be lost as part of
A2/A282 scheme.
Collection of Dittander seeds and plants and
translocation to new suitable location.
Vegetation
Translocation of calcareous grassland to Darenth
Country Park.
An area of calcareous grassland would be lost
along the A2 near Darenth Wood.
Loss of hedgerow due to A2/A282 scheme in
Disused Mabledon Hospital Grounds.
Loss of screening vegetation at Rams Wood
(ancient woodland) to east and west of M25.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
Translocation of hedgerow to safe location a few
metres from original position or steepening of
earthworks and protection of hedgerow during
construction to allow hedge to remain in-situ.
Replanting at edge of Rams Wood to replace lost
planting as part of landscaping proposals
New drainage has been implemented on both M25 and A2/A282
schemes and interceptors and attenuation ponds have been
implemented. No information has been provided to POPE which
would indicate that there has been any impact through surface water
pollution to Sutton-at-Hone Lakes SNCI, as expected in the ES.
The Managing Agent has confirmed that dittander was relocated to a
new site. However, it is not yet known whether this transplantation
was successful.
Further information on the success of the relocation has not been
made available to POPE and the FYA report should assess this
issue if monitoring data becomes available. The Managing Agent
confirmed that Calcareous grassland had been relocated to Darenth
Country Park. No further information has been made available to
POPE post-relocation.
The FYA report should assess this issue if monitoring data becomes
available. Hedgerow was not moved in eventuality and the HEMP
states that it was protected during construction by a retaining wall.
Long term monitoring and management of the hedgerow has been
committed to.
No evidence of replanting was noted at Rams wood during the site
visit. However, access was only possible to Rams Wood East. The
verge remained well wooded and replanting did not seem to be
required as shown in Figure 5.15.
98
Reptiles potentially present at areas required for
construction and areas of potential reptile habitat
lost at operation of each scheme.
Survey, trapping and relocation of reptiles in areas
affected by construction to safe areas.
New lighting may affect bat foraging. No bat
roosts directly lost through either scheme but
some foraging habitat lost.
Appropriate
lighting
to
be
implemented.
Landscape proposals including new planting will
help mitigate lost foraging habitat.
HEMPs for both schemes state that reptiles were captured and
relocated to safe habitats not affected by construction.
Newly created verges have provided new reptile habitat but
monitoring data has not been made available to POPE.
The HEMPs state that bat boxes have been installed on mature
trees and posts adjacent to attenuation ponds and next to the River
Darent.
Landscape planting proposals implemented as expected but not yet
mature.
Bats
Reptiles
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Badgers
Birds
Modern lighting with reduced light spillage has been implemented
across both schemes. No information has been made available to
POPE which would inform whether bat foraging has been affected
by the scheme lighting.
New lighting may affect birds.
habitat lost.
Some foraging
Appropriate
lighting
to
be
implemented.
Landscape proposals including new planting will
help mitigate lost foraging habitat.
Landscape planting proposals implemented as expected but not yet
mature. It is not known by POPE whether lighting has affected the
local bird population
Modern lighting with reduced light spillage has been implemented
across both schemes
Badgers close to construction works and living
within Darenth Wood.
Mitigation to be undertaken during construction.
HEMP states that appropriate mitigation was undertaken during
construction.
Badger fencing to be provided through Darenth
Wood to reduce badger deaths on A2.
Site visit showed badger
recommended within the ES.
fencing
had
been
installed
as
No animal mortality data has been made available to POPE for this
OYA study and will be requested again at FYA.
Dormouse
Potential dormouse habitat lost, particularly at
edge of Darenth Wood and Rams Wood.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
Replanting of habitat adjacent to Rams Wood and
Darenth Wood to replace lost habitat.
Agreement with HA and Natural England to be
sought to manage replanted verge and SSSI
adjacent to Darenth Wood for dormice.
Replanting has been undertaken in areas identified within ES.
Woodland not yet mature enough to be managed for dormouse
habitat.
According to the HEMP for the A2/A282, dormouse boxes have
been provided within Darenth Wood.
Ongoing monitoring has been undertaken for dormice. No survey
information has been made available to POPE and should be
provided to POPE for the FYA evaluation
99
Wood Ant
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Wood ant nests on embankments lost due to
widening of A2. The species is in decline
throughout its range.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
Translocation of wood ant nests to pre-prepared
sites at edge of Darenth Wood SSSI and 2 year
post-translocation monitoring programme.
100
HEMP for A2/A282 states that ants were moved in 2006 and 2007.
Monitoring was undertaken and has shown that 2006 colonies were
generally abandoned, but 2007 colonies proved more successful.
The HEMP considers that the wood ant population along the A2
embankments has been safeguarded.
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Water Quality and Drainage
Forecast
A2/A282
5.121
The AST stated that soakaways would be relocated or replaced with balancing ponds. Enhanced
pollution control would be implemented before discharge. This would have a slightly beneficial
impact on the water environment.
5.122
The ES predicted that there would be a reduced pollution threat to the River Darent and source
protection zone due to provision of balancing ponds and removal of existing soakaways. New
soakaways would be provided in areas less vulnerable to groundwater pollution and pollution
control features such as oil separators would also be implemented on all discharges to
groundwater and the River Darent.
5.123
Due to mitigation measures and flood compensation the scheme would have a neutral impact on
flood risk.
M25 J1b-3
5.124
The AST stated that provision of pollution facilities, including spillage containment and oil
interception at outfall locations, would result in improved pollution control, resulting in a benefit in
terms of protecting groundwater quality, meaning an overall slight beneficial assessment score.
5.125
The ES stated that the scheme would increase run-off due to additional lanes, meaning greater
flow at discharge points. There would be a changed risk of spillage due to new lanes, lane-widths
and traffic management, and changes to the scheme hydrology and drainage.
5.126
The M25 drainage would discharge to ground at fewer locations than the Do Minimum and
impacts would be mitigated by installation of pollution control measures at each discharge,
improving pollution control and reducing risk to ground and surface waters. A vegetative
treatment pond would also be provided at Pond 3. The result of the scheme would be a predicted
slightly beneficial impact.
5.127
Due to mitigation measures and flood compensation the scheme would have a neutral impact on
flood risk.
Consultation
5.128
The Environment Agency stated that it did not have any monitoring data available, but expected
water quality to have improved if all mitigation stipulated in the ESs was implemented. Jacobs’
Handover Water Quality Monitoring Report (March 2010) was not available in time to consult the
EA with and so they should be consulted at FYA stage.
Evaluation
5.129
The HEMP and as-built drainage drawings for both schemes illustrate that all mitigation has been
implemented as expected. Water from both schemes was previously discharged – unmitigated –
to ground through soakaways but is now captured through pollution controlled drainage and
treated. The risk to ground and surface waters by spillage has now also been mitigated, and a spill
event on either the A2, A282 or M25 will now be intercepted before discharge to ground or to the
River Darent.
5.130
The Managing Agent confirmed that there were no spill events during construction or since and
this is supported by the data available in the Handover Water Quality Monitoring Report. The
report noted that there is litter within the drainage and surface waters associated with both
schemes, and summarised that “the water in each environment; groundwater, natural surface
water and highways drainage, was fairly consistent with little change over the monitoring period.
However, as not all of the monitoring locations were consistently visited or sampled from, direct
correlation is difficult to assess. The only locations which were generally visited on each occasion
were the surface water locations along the river - which could be argued to be the most important
as an indicator of contamination from the Works. A more in-depth look consideration of the results
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
101
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
from these locations indicates little if any change in the quality of the water over the period of the
works.
5.131
It is recommended that, if possible, water quality monitoring is continued and reported again at
FYA stage. Efficacy of mitigation measures in relation to spill events should also be assessed at
FYA.
5.132
New drainage installed on each scheme to cope with run-off from additional lanes and links
carries all run-off to the edge of the carriageway to single discharges, some of which are mitigated
by baffled spillways to reduce flow-speeds (see Figure 5.17). Spillage containment tanks and oil
interceptors then intercept run-off before discharge into attenuation ponds. Figure 5.18 shows
such an attenuation pond – Combined Pond A – which was provided as part of the A2/A282
scheme. Towards the centre of the photograph it is possible to see the outlet / flow control
structure with isolated penstock, which discharges to the River Darent.
Figure 5.17 – Baffled spillway to north-west of M25 J2
Figure 5.18 – ‘Combined Pond A’ to the north-west of M25 J2
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
102
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.21 – Summary of Water Evaluation – A2/A282
Summary of Water Impacts
Origin of
Assessment
Assessment
AST
(forecast)
Soakaways relocated and/or replaced with balancing
ponds.
Enhanced pollution control facilities before
discharging into river.
Slight beneficial
EST
Soakaways have been replaced with balancing ponds.
Oil separators have been installed at all discharge points
and spillage containment tanks, baffled spillways and
penstocks have also been installed to mitigate water
pollution impacts. Mitigation has been implemented as
expected. Monitoring data suggests that there has been
no significant change in water quality as a result of the
scheme.
Likely to be as
expected
(OYA
evaluation)
Table 5.22 – Summary of Water Evaluation – M25 J1b-3
Summary of Water Impacts
Origin of
Assessment
Assessment
AST
(forecast)
Water features in the study area are typical of the
locality with a major aquifer (chalk) providing abstraction
water, and the River Darent crossing under the M25.
Provision of pollution control facilities, including spillage
containment and oil interception at outfall locations, will
result in improved pollution control, resulting in a benefit
in terms of protecting groundwater quality.
Slight beneficial
EST
Soakaways have been replaced with balancing ponds.
Oil separators have been installed at all discharge points
and spillage containment tanks, baffled spillways and
penstocks have also been installed to mitigate water
pollution impacts. Mitigation has been implemented as
expected. Monitoring data suggests that there has been
no significant change in water quality as a result of the
scheme.
Likely to be as
expected
(OYA
evaluation)
Physical Fitness
Forecast
5.133
The ASTs for both schemes predict no changes to distances travelled by non-motorised users and
a neutral impact on physical fitness.
5.134
The ES for both schemes noted that there would be no physical change to any public rights of
way, with the exception of a slight diversion of footpath DR36 near Blackdale Farm Cottages. The
possible depreciation to amenity value for public rights of way crossing and situated close to the
schemes was predicted. There would be no additional severance of recreational or community
land for either scheme. A neutral impact was predicted for non-motorised users.
Consultation
5.135
No comments on physical fitness have been made by consultees.
Evaluation
5.136
A number of public rights of way were severed when the existing M25, A2 and A282 were
constructed. The M25 J1b-3 and A2/A282 schemes did not seek to mitigate any of this pre-
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
103
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
existing severance; neither do they cause any additional negative material effects to any public
rights of way. This is as expected.
5.137
A number of public rights of way pass close to the schemes and have been affected by the
scheme by changes in views. These impacts are tempered by the pre-existing character of the
landscape, already dominated and severed by the M25, A2 and A282.
5.138
With the exception of DR36, no public rights of way have been materially affected by either
scheme. Figure 5.19 shows DR36 (to the right of the carriageways), which has been moved
slightly to skirt the edge of the new embankment supporting Link A at M25 J2. It is considered
that this diversion has had a negligible change to the footpath, as expected in the ES.
Figure 5.19 – Diversion to footpath DR36
Table 5.23 – Summary of Physical Fitness Evaluation – A2/A282
Origin of
Assessment
Summary of Physical Impacts
Assessment
AST
(forecast)
No change to distances walked or cycled
Neutral
EST
Public rights of way are unaffected by the scheme and
there is no new severance.
As expected
(OYA
evaluation)
Table 5.24 – Summary of Physical Fitness Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Physical Impacts
Assessment
AST
(forecast)
The health benefits would remain unchanged as there
are no changes to the public right of way network
Neutral
EST
Apart from minor changes to footpath DR36, public
rights of way are unaffected by the scheme and there is
no new severance.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
104
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Journey Ambience
Forecast
A2/A282
5.139
The AST predicted that journey ambience would be improved through reduced congestion and
improved signage, with a slightly beneficial impact.
5.140
The ES commented on driver stress, predicting that it would be improved due to reduced
congestion, and traveller care would also be improved by provision of new signage.
M25 J1b-3
5.141
The AST stated the scheme would be beneficial due to reduced congestion, improved road layout,
signage and lighting, tempered by the possible perception of fear of accidents due to reduced lane
width.
5.142
The ES predicted that:

Traveller views would be opened at OYA stage due to removal of vegetation, but views would
largely be unchanged after design year due to establishment of planting.

Driver stress would be improved by reduced congestion at peak times and provision of more
road space.

Traveller care would be improved by new gantries and signage and implementation of new
lighting.
Evaluation
5.143
The Journey Ambience sub-objective considers Traveller Care (facilities and information),
Traveller Views and Traveller Stress (frustration, fear of potential accidents and route uncertainty).
Traveller Views
5.144
Traveller views are generally as expected, although additional height of 3m barriers (rather than
2m high barriers as presented in the ES) along additional lengths of the M25 will have constrained
predicted views.
Driver Stress
5.145
Driver stress should have generally reduced on both schemes due to the reduction in congestion
(this may be due to less traffic growth, as a result of recession) and thus reduced frustration.
Improved links on the A2/A282 scheme has improved route certainty and fear of accidents and
improved signs and signals on both are likely to have further reduced driver stress by improving
route certainty. Improved lighting would have also reduced fear of accidents. Narrower lanes on
the M25 may have possibly contributed to drivers’ fear of accidents.
Traveller Care
5.146
Gantries and lighting have been implemented as expected, improving driver information.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
105
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table 5.25 – Summary of Journey Ambience Evaluation – A2/A282
Origin of
Assessment
Summary of Journey Ambience Impacts
Assessment
AST
(forecast)
Less congestion and stress reduced due to improved
signing
Neutral
EST
New gantries and signage have improved driver
information. Provision of more lanes and new junction
layouts have generally improved journey times.
Additional lighting will have improved night time driving
conditions.
As expected
(OYA
evaluation)
Table 5.26 – Summary of Journey Ambience Evaluation – M25 J1b-3
Origin of
Assessment
Summary of Journey Ambience Impacts
Assessment
AST
(forecast)
The proposals are beneficial in terms of anticipated
reduction in traffic, improved road layout, signage and
lighting. However, this is balanced by reduced lane
width possibly causing increased fear of accidents.
Neutral
EST
New gantries and signage has improved driver
information. Provision of more lanes and should have
generally improved journey times. Additional lighting will
have improved night time driving conditions. Driver
views are more restricted than expected due to
implementation of higher environmental barriers on
additional lengths of the scheme.
As expected
(OYA
evaluation)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
106
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Key Points from Environment Section
 Noise – On the M25, it is likely that local noise impacts are generally better than expected
due to traffic flows being lower than forecast (possibly due to recession impacts) and
improved noise mitigation. For the A2/A282 scheme, it is likely that overall local noise
impacts are generally as expected based on overall traffic impacts compared to forecast;
 Local Air Quality – As with noise, based on traffic flows, it is possible that local air quality
impacts are generally better than expected on the M25 and as expected for the A2/A282
scheme. There should be no worsening of air quality at AQMAs, as expected.
 Greenhouse Gases – The proportional increase in opening year carbon emissions is as
predicted for the A2. Opening year emissions on M25 are similar to the only published
forecast which is for 2022.
 Landscape – Mitigation measures generally provided in line with proposals. Too soon to
evaluate establishment of new planting and seeding which should be reviewed as part of
the FYA report. Visual impacts and landscape effects are considered to be generally as
predicted at OYA.
 Biodiversity – There have been no direct impacts as a result of either scheme to any
designated sites, but indirect effects on Darenth Wood SSSI due to vegetation loss adjacent
to the A2 as expected. Mitigation has been implemented generally as expected.
Translocation of species and habitats has generally been undertaken as described in the
ES but - with the exception of wood ants, which proved successful - monitoring data has not
been made available to POPE to confirm the success of relocation.
 Cultural Heritage – Based on the information available it is considered that impacts of the
M25 scheme are as expected. Impacts to Listed Buildings and the Scheduled Monument at
Hawley Manor are better than expected due to screening of traffic by environmental
barriers.
 Water –It is considered that the impacts of both schemes are as expected as mitigation
measures have been implemented as planned. Water quality reporting suggests that there
has been no significant change to water quality as a result of the schemes.
 Physical Fitness – Impacts on public rights of way and community land were predicted to
be minimal for both schemes and were generally limited to visual impacts. As such, the
neutral impact for both schemes is as expected.
 Journey Ambience - Congestion has been reduced on both schemes (this is partly due to
traffic growth predictions not being realised, possibly due to recession impacts), the routes
are well signed - removing uncertainty - and new links have generally improved vehicle
movements between the schemes. This is tempered by reduced lane widths on the M25,
which increase fear of accidents. Views from certain areas of the M25 may be more
restricted than expected at OYA stage due to increased height and length of environmental
barriers, but impacts on journey ambience are generally as expected.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
107
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
6.
Accessibility and Integration
Introduction
6.1
Accessibility and Integration are the remaining objectives of the five Government objectives for
transport. As part of each scheme’s appraisal, forecasts for the impacts on these objectives were
covered in the AST (see Table D.1 / D.2 and Table D.3) and formed part of the schemes’ preopening assessments.
Data Sources
6.2
The evaluation presented here is based on the site visit and on literature searches. Forecast
impacts are available from the ASTs for each scheme.
6.3
For the M25 scheme, Stage 3: Scheme Assessment Report Part 2 Engineering, Traffic and
Economics section (SAR) also included accessibility objectives.
Option Values
6.4
Option values, as defined in WebTAG, largely relate to measures which will substantially change
the availability of transport services within the study area.
Forecast
6.5
The forecast impacts of the A2 and M25 schemes were both no impact.
Evaluation
6.6
It is considered that appraisals are valid for both schemes and that no more detailed evaluation
would reveal any changes to options values connected with the schemes.
Severance
6.7
This sub-objective is concerned with severance as it affects those using non-motorised modes,
especially pedestrians.
Forecasts
A2/A282 scheme
6.8
The AST stated that the existing junction already caused severance and assessed the impact as
neutral.
6.9
A Pedestrian and Cyclist Report was prepared at OPR stage (May 2004). This states that the
junction was unsuitable for use by cyclists and pedestrians in both its then existing form and that
proposed in the scheme.
6.10
Use of the A2 by pedestrians was described as minimal or non-existent due to the lack of
infrastructure and was only likely to occur as a result of vehicle breakdown or accident. The
nature of the road meant that equestrian users did not use the route.
6.11
Cyclists were permitted on the A2 and A282, although the study identified a number of conflict
zones at the junction. The National Cycle network passes through J1b and Dartford town centre.
Consultation with the Kent CC Cycling Officer confirmed that no cycling provision was required for
this scheme.
6.12
The report concluded by recommending that:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
108
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Pedestrians, cyclists and equestrians be prohibited by a Traffic Regulation Order from using
or crossing the A2 between the Bean junction and the Dartford Heath junction and from the
A282 south of J1b. Appropriate signage would be provided;

An alternative route for cyclists be signposted between the A2 at Bean and the Dartford
Heath junction via the National Cycle Route 1 where appropriate; and

No mitigation measures were required for other vulnerable users.
6.13
The ES stated that in general, off-road rights of way for pedestrians, cyclists and equestrians were
not expected to be impacted by the scheme. The promotion of transport such as walking and
cycling within Dartford would not be prejudiced by the Scheme.
6.14
In the Environmental Impact Tables, assessment of the impact of the scheme for Pedestrians,
Cyclists and Equestrians was:

No new severance would be created; and

Only change in amenity value would be a minor diversion to one footpath near Blackdale
Farm Cottages (DR36), north-west of the junction.
M25 scheme
6.15
The AST stated that five footpaths ran close to the widening, and two crossed over this section of
the M25 but none would be affected by the scheme.
Evaluation
6.16
The as-built drawings confirm that the impacts on rights of way are as predicted. The only
footpath diversion is minor, makes negligible change to its route length or amenity value. This
was confirmed by the site visit.
Figure 6.1 – Relocated Stile on footpath DR36
Access to the Transport System
6.17
WebTAG states that access to the transport system is strongly influenced by the two key variables
introduced at the start of this section, i.e. access to a private car and proximity to a public
transport service.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
109
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Forecast
A2/A282
6.18
The original AST stated that neither benefits to existing network nor increased opportunities for
public transport initiatives were assessed.
6.19
The later AST compiled following the completion of construction additionally said that it would
facilitate access to Ebbsfleet International station and to regeneration areas.
6.20
The assessment in both ASTs was neutral.
M25 J1b – 3
6.21
The AST stated that although access to public transport systems (e.g. Ebbsfleet railway station) is
improved, the scheme does not form part of a public transport route. Hence the assessment was
neutral.
6.22
The SAR stated that the scheme’s accessibility objective included:

Facilitating access to Ebbsfleet International Rail Station; and

Improving access to regeneration areas of North and East Kent
Evaluation
6.23
It is not possible to evaluate the impacts using the webTAG 'Access to the transport system'
indicator current at the time of the schemes’ appraisals because this was based on the impacts for
the local population without access to a car and data on the local public transport services. These
schemes have had no impact on local bus routes or bus stops. The analysis in the traffic section
of this study has shown no clear impact on traffic flows on the local roads in Dartford hence no
impact on bus reliability can be inferred.
6.24
Draft guidance for the accessibility objective (TAG Unit 3.6.3 January 2010) replaces the Access
to the Transport System sub-objective. This new guidance recognises the link between transport
and social exclusion of vulnerable groups. These groups include older people and people in receipt of
Jobseekers Allowance. It is however considered that the schemes have produced real benefits for
members of these groups who have access to a car in terms of journey times and reliability to
destinations including:
6.25

Employment opportunities in Regeneration areas;

Ebbsfleet Station which opened in November 2007; and

Retail facilities at Bluewater shopping centre.
It is not possible to quantify these access benefits. The overall evaluation is this conservatively
concluded to be slight beneficial for both schemes.
Integration
6.26
The integration objective is to ensure that all decisions are taken in the context of the
Government's integrated transport policy.
6.27
The forecast integration objectives were given in the AST for each scheme for each of the
integration sub-objectives:

Transport interchange

Land-use policy

Other Government policies
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
110
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
A2/A282
Forecast
6.28
The scheme formed an integral part of public transport based strategy for Kent and Thameside
development and hence was assessed to be moderate beneficial for the transport interchange
sub-objective.
6.29
The impact on policy objectives was assessed as adverse due to loss of good agricultural land,
and the direct and indirect effect on Green Belt, nature and heritage conservation designations
which are contrary to local and national policy objectives.
Evaluation
6.30
Kent Thameside forms part of the Thames Gateway area of regeneration as set out in the
Government’s Thames Gateway Interim Plan (2006). For Kent Thameside this means the
delivery of 25,000 homes and 50,000+ jobs by 2026.
6.31
The scheme is consistent with the Kent Thameside Strategic Transport Programme which
supports delivery of this programme and has therefore been evaluated to have a beneficial
impact, as expected.
6.32
The omission of link E from the as-built scheme will have slightly reduced the adverse impact on
heritage policy, but otherwise the scheme’s impact on land use policy and other government
polices is adverse as forecast, and therefore the evaluation of the impacts is as expected.
M25 J1b – 3
Forecast
6.33
This scheme was forecast to have a neutral impact on all of the integration sub-objectives.
6.34
No transport interchanges would be affected by the scheme.
6.35
In terms of land use policy and other government policies, the scheme was consistent with
policies supporting a reduction in congestion and network capacity enhancement whilst having a
slight adverse impact on some local environmental policies.
Evaluation
6.36
The forecast capacity and congestion improvements have been met by this scheme. The
environmental impacts of this widening scheme, as detailed in the environment section of this
report, are clearly less than the A2/A282 scheme. Therefore the evaluation of the overall policy
impact is assessed to be neutral, as expected.
6.37
The OYA evaluation is that these forecast impacts have been as expected for each sub-objective.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
111
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Key Points from Accessibility and Integration Section
Accessibility (A2/A282 and M25 J1b – 3)
 Option Values and Severance – no impact as expected.
 Access to the Transport System – improved access to employment and retail for car
users, improved access to new Ebbsfleet International Station.
Integration- A2/2A282
 Transport Interchange – A2/A282 scheme is part of wider transport strategy for Kent
Thameside regeneration area.
 Land Use Policy – adverse as expected.
 Other government policies – adverse as expected.
Integration – M25 J1b
 Transport Interchange – no impact as expected.
 Land Use policy –neutral overall impact as expected.
 Other Government Policies – neutral overall impact as expected.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
112
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
7.
Conclusions
Measurement against NATA Objectives: AST &
EST
7.1
The appraisal of each scheme against the NATA objectives was given in Appraisal Summary
Tables (AST). The Appraisal Summary Table (AST) is a one page summary of a scheme
covering the Government’s five goals for transport taking into account of all the economic, social,
environmental and financial impacts of an intervention.
7.2
The AST therefore provides a checklist against the standard set of objectives.
7.3
Evaluation of accuracy of the AST forecasts is summarised in a POPE table called the Evaluation
Summary Table (EST).
7.4
The AST and EST tables for these schemes are given in Appendix D.
Measurement against Scheme-specific
Objectives
7.5
The performance of the A2/A282 and M25 schemes, against the specific objectives of the
schemes, as opposed to the NATA ones are as follows, followed by brief details of the basis of the
evaluation.
7.6
The objectives listed here are based primarily on the Scheme Assessment Report for each
scheme, with some additional details from the Statement of Case, AST or ES of each scheme.
Traffic and Economy
Objective
Objective
Fulfilled?
Improve journey times and reliability on A2 (A2/A282)


Reduce journey times by 30-60 seconds and improve reliability on M25
(M25 J1b-3)

Provide good value for money for business users and consumers (both
schemes)

Facilitate future demand management measures1 to provide some constraint
on induced traffic and lock in benefits from widening. These measures
would be carried out separately from this scheme. (M25 J1b-3)

Reduce congestion and improve reliability at M25 J2 (A2/A282)
Support objectives of the Regional Planning Guidance for South-East
(RPG9) and the Thames Gateway Planning Framework (RPG9a).
(M25 J1b-3)

1
At the time of appraisal, several types of measures were under consideration including Controlled
Motorway, Ramp Metering, and controlled access using existing signals on roundabouts.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
113
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
7.7
The journey time surveys in the traffic section of this report show:

Reduced journey times for the key movements at the junction;

Reduced journey times on the A2 and M25; and

Reduced variation in journey times on A2 and M25.
These observations show that the first 3 objectives above have been met.
7.8
The economic evaluation of the outturn costs and reforecast of the benefits money over the 60
year appraisal period shows that the overall BCR for the two schemes combined is 2.2,
representing good value for money.
7.9
Provision of infrastructure for a Controlled Motorway system on the M25 at the same time as the
widening scheme evaluated here will have improved incident detection. Arguably, when the
variable speed limits of the CM are activated, this will lock in the benefits of the widening scheme.
7.10
The schemes are consistent with regional planning guidance.
Safety
Objective
Objective
Fulfilled?
Improve safety on A2 / A282 and M25 (both)

Improve safety on nearby local roads due to reassignment of traffic onto the
M25 and A2 (both)
?
Improve security through use of CCTV (both)

7.11
The safety section of this report shows improved safety through reduced accident numbers on
both the M25 and on the A2, despite increased traffic on the latter.
7.12
It is not possible to evaluate the safety impact on the local road network because this was forecast
to be very small and was based on traffic rerouting from these roads to the motorway and trunk
road network. The traffic data does not indicate clear evidence of rerouting from the local roads
and any small accident saving on these roads would be impossible to distinguish from statistical
noise and possible larger impacts on safety through local authority safety measures.
7.13
CCTV has been installed around the junction and on the M25.
Environment
Objective
Minimisation of environmental impacts through low noise surfacing, noise
barriers and full cut-off lighting (A2/A282 and M25 J1b-3)

Minimisation of environmental impacts through construction of scheme
within existing highway boundary (M25 J1b-3)

?
Improve water pollution control measures (M25 J1b-3)
7.14
Objective
Fulfilled?
The environment section of this report shows that mitigation measures have been put in place.
Where data exists, these have shown to be working. At this stage it is too soon to evaluate
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
114
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
impacts on landscape and biodiversity which take longer to come into full effect. Water monitoring
data is required to confirm the success of the improved pollution control measures.
Accessibility and Integration
Objective
Objective
Fulfilled?
Provide access to new Ebbsfleet International station from the national
motorway and trunk road network (both)

Provide beneficial economic impacts to Kent Thameside Regeneration Area
(both)

7.15
Ebbsfleet International Station opened in November 2007, just prior to the completion of the
A2/A282 scheme. Access to the station is clearly benefited by the improvements to the A2, the
junction and the M25.
7.16
At this stage post scheme completion, and in a recession, it is not feasible to measure actual job
creation linked to the scheme. The regeneration area will be able to benefit from the
improvements to journey times and reduced congestion.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
115
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Appendix A Summary of Sources
A.1.1
The sources upon which this evaluation is based include the following:

Traffic counts and journey times from the Highways Agency’s databases, and surveys
specifically commissioned for this study;

Accident records obtained from the HA MACs for Area 4 (A2 in Kent) and Area 5 (M25 and
A2 within M25);

A site visits by a transport planner and a landscape architect;

Consultation with the local authorities and statutory environmental bodies;

Reports appraising the scheme, prior to construction as detailed below.
A2/A282 Dartford improvement

A2/A282 Dartford Improvement & M25 J1b - J3 Rapid Widening Traffic Survey (March 2005)

A2/A282 Dartford Improvement Statement of Case (January 2004)

Inspectors Report (March 2004)

Pedestrian and Cyclist Report (May 2004)
Public Inquiry:

Traffic & Economics Proof of Evidence Summary (January 2004)

Engineering Proof of Evidence (Jan 2004)

Proof of Evidence documents for Environment objectives (Landscape, Archaeology, Ecology,
Noise & Vibration, Air Quality, Water Quality) (January 2004)
OPR stage:
A.1.2

Traffic Forecasting Report (June 2002)

Economic Assessment Report Part 1: Methodology (June 2002)

Economic Assessment Report Part 2: Economic Assessment (December 2003)

A2/A282 Dartford Improvement Environmental Statement Volumes 1 & 2 (March 2003)
Sources for the appraisal of the modified version of the Dartford Improvement scheme known as
Link E deferred:

Economic Assessment Report Addendum II (June 2006)

Report on Deferment of Link E and Revised Landscape and Drainage Attenuation Proposals
in North West Quadrant of Junction 2 (April 2006)

Appraisal Summary Table Comparison (January 20081)
1
Note that this was a post opening review of the link E deferred scheme which updated the previous AST for
the earlier version of the layout.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
116
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
M25 J1b-3 Widening

M25 Rapid Widening – Summary and Implementation Strategy Report (May 2004)

Volume 3A M25 Rapid Widening - Section 3 - Junction 1b-3 Stage 1 Report: (May 2004)

Volume 3B M25 Rapid Widening - Section 3 - Junction 1b-3 Stage 1 Report: (May 2004)

M25 Rapid Widening Scheme Section 3 Junctions 1b to 3 – Environmental Scoping Report
(August 2004)

M25 – Section 3 Junctions 1b To 3 Phase 1 Habitat Survey (February 2005)

Appraisal Summary Table Date: 1/12/06. Stage 3 - Version IFU Rev 1

A2/A282 Dartford Improvement & M25 J1b - J3 Rapid Widening Traffic Survey (March 2005)

M25 J1b to J3 Widening Scheme Order Publication Report (October 2006)

M25 J1b to J3 Environment Statement and Non-technical Summary(November 2006)

Stage 3 Scheme Assessment Report : Engineering Traffic and Economics (November 2006)

Economic Assessment Report Addendum (Sept 2006)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
117
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Appendix B Scheme Objectives
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
118
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Details of the objectives as stated in published documents during appraisal
stages of each scheme are given below.
B.1 A2/A282 Dartford Objectives
B.1.1
B.1.2
B.1.3
The Stage 3 Scheme Assessment Report gives the objectives at the Order Publication Report
(OPR) stage as:

To improve the flow and safety of traffic at the interchange of the A2/A282, together with the
provision of a dual four lane carriageway in each direction on the A2, east of the M25;

To limit the environmental impact of the Scheme, and to reduce noise impact on adjacent
residential properties. In particular, to limit the impact on the Darenth Wood Site of Special
Scientific Interest (SSSI) and the Darenth Wood Scheduled Ancient Monument (SAM);

To improve safety at the junction by reducing congestion and the consequent queuing of
traffic back onto the A2, A282 and M25;

To reduce journey times and improve reliability in order to provide enhanced access from the
M25 to the major regeneration area of Kent Thameside, as part of the Thames Gateway
Planning Framework RPG9a. Also to improve access to other regeneration areas in North
and East Kent, helping to support jobs and prosperity;

To facilitate access to Ebbsfleet International Rail Station from the national motorway and
trunk road network; and

To be part of and to support other elements of an integrated and sustainable public transport
based strategy for the Kent Thameside regeneration area.
The scheme’s objectives as given in the 1998 Roads Review were to:

Reduce congestion at the junction of A2 and A282;

Provide additional road capacity to cater for predicted future traffic growth; and

Improve accessibility of the Thames Gateway area.
The Statement of Case (2004) and Environmental Statement (2003) documents both give the
scheme objectives as:

To improve the flow and safety of traffic at the interchange of the A2/A282, together with the
provision of a dual four lane carriageway in each direction on the A2, east of the M25;

To limit the environmental impact of the Scheme and to reduce noise impact on adjacent
residential properties. In particular, to limit the impact on the Darenth Wood Site of Special
Scientific Interest (SSSI) and the Darenth Wood Scheduled Ancient Monument (SAM);

To improve safety at the Junction by reducing congestion and the consequent queuing of
traffic back onto the A2, A282 and M25;

To reduce journey times and improve reliability in order to provide enhanced access from the
M25 to the major regeneration area of Kent Thameside, as part of the Thames Gateway
Planning Framework RPG9a. Also to improve access to other regeneration areas in North
and East Kent, helping to support jobs and prosperity;

To facilitate access to Ebbsfleet International Rail Station from the national motorway and
trunk road network; and

To be part of and to support other elements of an integrated and sustainable public transport
based strategy for the Kent Thameside regeneration area.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
119
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
B.2 M25 J1b – 3 Objectives
B.2.1
B.2.2
B.2.3
The objectives of the M25 J1b - 3 widening scheme can be summarised based on the AST (2006)
as:

To improve journey time reliability;

To reduce journey times for consumers and business users by 30-60 seconds in the opening
year and increasing in future years;

To provide beneficial economic impacts due to journey time reliability improvements:
-
Increased labour pool within Kent Thameside Regeneration Area;
-
Job creation for residents of Kent Thameside Regeneration Area through increasing the
labour pool;
To improve security through CCTV and improved emergency call facilities; and

To improve safety on nearby local roads due to reassignment of traffic onto the M25.
The Scheme Assessment Report (SAR) included details of the objectives of this scheme against
the Government’s five key objectives for transport (NATA). These include those listed above and
the following:

In terms of environmental objectives, the scheme would seek to minimise adverse impacts on
noise, air quality, landscape, and the water environment;

Support objectives of the Regional Planning Guidance for South-East (RPG9) and the
Thames Gateway Planning Framework (RPG9a); and

Facilitate demand management measures to provide some constraint on induced traffic and
lock in benefits from widening, which were to be developed, together with improvements to
junctions and incident detection measures. This development work would be carried out
separately, by others, to the development of the widening Scheme, but there would be close
liaison between those taking forward the different work streams. The implementation of any
emerging demand management measures would be coordinated with the Scheme.
Additionally to the NATA objectives, the SAR stated that:
The M25 scheme was to be packaged with A2/A282 Dartford Improvement in order to avoid
abortive construction work, limit the disruption to road users by completing the two Schemes
within the minimum possible time, and minimise the overall cost.
The Environment Statement (ES) included a full set of scheme objectives including those above
and:


B.2.5
Benefits to existing and future transport-reliant businesses;


B.2.4
-
To minimise the environmental impacts through the use of:
-
Lower noise surfacing to minimize noise levels;
-
Environmental barriers in the Hawley area to reduce adverse visual impacts for
properties and provide noise attenuation; and
-
Full cut-off lanterns to minimise the visual impact of the lighting; and
To produce a positive effect on the environment with the inclusion of up to date pollution
control facilities and the incorporation of vegetative treatment of the surface water run-off
prior to disposal via soakaway.
Although the planned Controlled Motorway (CM) was not directly part of this scheme, one of the
objectives of this scheme (as stated in the ES) was:
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
120
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study

Provision of sufficient communications infrastructure and sign gantries to facilitate the
incorporation of variable speed limits for Controlled Motorway. This would produce more
reliable journey times hence supporting the objective of reducing driver stress.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
121
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Appendix C Environmental Sources
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
122
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
C.1 Standard list of information required to evaluate
the environmental sub-objective
Information Requested
Environmental Statement (ES) (or Stage 3 Scheme Appraisal
Report)
Information Received
 M25 junctions 1b to 3
Widening Scheme ES,
November 2006: Volume
1A – main text; Volume
1b – figures; Volume 3 –
appendices;
NonTechnical Summary.
 A2/A282
Dartford
Improvement ES, March
2003: Volume 1 – main
text and appendices;
Volume 2 – figures.
Appraisal Summary Table (AST)
 A2/A282
2004.
AST,
January
 A2/A282 AST Link
Deferral, June 2006.
 M25
2006
Amendments, updates or addendums to the ES or relevant
further studies or reports.
AST,
E
December
 A2/A282
Dartford
Improvement Report on
Deferment of Link E and
Revised Landscape and
Drainage
Attenuation
Proposals in North West
Quadrant of Junction 2,
Issued at IFI, April 2006.
 A2/A282
Dartford
Improvement
AST
Comparison, Issued at
IFI, January 2008.
‘As Built’ drawings for landscape, ecological mitigation
measures, drainage, fencing, earthworks etc.
Not yet completed for
landscape and ecology.
 A2/A282
drainage
drawings received.
 M25 drainage drawings
received.
Landscape and Ecology Management Plans
Not yet completed, but
generic HEMPs received for
both schemes.
Relevant contact names, of people with knowledge of the
scheme at:
 the Statutory Consultees (Environment Agency, English
Heritage and Natural England);
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
Contact details received
123
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Information Requested
Information Received
 the local authorities;
 parish councils
 the designer or environmental coordinators for the scheme
and for the MAC; and,
 any other relevant specialist consultees that were contacted
Archaeological reports (popular and academic)
Not yet completed. Due for
completion later in 2010.
List of properties eligible for noise insulation
No properties eligible for
noise insulation
List of Part 1 Claims regarding noise, air quality or lighting (from
HA National Part 1 Team)
Due to be received by FYA
stage.
Results of any post opening survey or monitoring work, e.g.
ecology surveys.
Not made available to POPE.
Animal mortality data, pre and post scheme construction (from
MAC)
Not made available to POPE
Water quality monitoring data
A2/A282 Dartford
Improvement & M25 J1b-J3
Widening Scheme Handover
Water Quality Monitoring
Report.
Scheme newsletters or publicity material for the scheme.
Material utilised from HA
website.
Copy of the Non-Motorised User (NMU) post opening survey
No NMU survey completed
for either scheme due to lack
of impacts on NMUs
Information available regarding environmental enhancements to
streetscape/townscape for bypassed settlements
N/A
Employer’s Requirements Works Information - environment
section
Not made available to POPE
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
124
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Appendix D
Appraisal Summary Tables & Evaluation
Summary Tables
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
125
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
D.1 Appraisal Summary Table
D.1.1
The Appraisal Summary Table (AST) is a one page summary of the scheme covering the
Government’s five goals for transport taking into account of all the economic, social,
environmental and financial impacts of an intervention. The NATA AST is designed to provide
decision takers with a concise overview of impacts across the board.
A2/A282 scheme
D.1.2
Several ASTs have been compiled for this scheme since it first entered the TPI programme in
1998 including:

Initial AST for 1996 Scheme (1998)

Key Stage 3 AST for Public Inquiry (Jan 2004)

Key Stage 4 AST (start ECI phase 2) taking into account deferral of Link E (June 2006)
D.1.3
Normally the Stage 3 version of the AST as shown in Table D.1 would be the final version, but in
this case the decision to defer Link E mean that further appraisal was undertaken including the
revision of the AST. The final revised AST is shown in Table D.2
D.1.4
The important changes between the last two versions are:
D.1.5

The removal of the construction of Link-E (free-flow A2 eastbound to A282 northbound) from
the scheme;

The addition of the M25 J1b – 3 widening scheme

Change of normal appraisal period from 30 to 60 years and price base year to 2002.
These changes are reflected in changes in the assessment for the sub-objectives:

Accidents – a small increase in economic benefit linked to revised price base

Economy – increases in both the cost of the scheme to public accounts and the Transport
Economic Efficiency benefits. These are primarily due to the change in price base, appraisal
period and reducing discounting rate rather than from Link E.

All other sub-objectives were considered to be unchanged by the deferral of Link E.
M25 J1b – 3
D.1.6
The AST for the M25 widening is shown in Table D.3. This was prepared shortly before the start
of construction and is for the scheme without the Controlled Motorway in operation.
D.2 Evaluation Summary Table
D.2.1
In order to ascertain the accuracy of predictions made prior to the scheme construction, a review
of the AST has been undertaken. Whilst the AST format is a standard from the NATA process,
the Evaluation Summary Table (EST) has been devised for the POPE process to record a
summary of the outturn impacts for the NATA objectives, compared to the predictions in the AST.
D.2.2
Where possible, the format of the EST mirrors the appearance and process of the AST to enable
comparison between the two.
D.2.3
The ESTs for these schemes are shown in Table D.4 and D.5.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
126
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table D.1 – Appraisal Summary Table: A2/A282 Dartford Improvement (Stage 3 assessment, Jan 2004)
Appraisal Summary Table (REV 2) A2 / A282 Dartford Improvement
Option:
Description:
Problems: Junction needs improvement and A2 needs
widening to avoid peak period
Present Value of Costs to Government
£70.4m (all costs are 1998 values
discounted to 1998)
QUALITATIVE IMPACTS
QUANTITATIVE ASSESSMENT
ASSESSMENT
No properties would experience an increase in noise levels in the Design Year (2022) due to use of low noise surfacing, mounds and fencing. 51 properties
would experience a reduction in noise levels of between 0.7 and 7.5 dB(A), 20 of which would experience a reduction greater than 3 dB(A). Without the
Scheme, use of low noise surfacing in the Design Year would mean 45 properties would experience a reduction of between 1 and 3dB (A).
No. of properties experiencing:
30 less people highly annoyed in 2022
Improvement comprising free flow links for E-N, N-E and W-N movements. Includes 3 multi-span viaducts and 4 further interchange bridges. Also includes
2km of A2 widening between M25 and Bean.
OBJECTIVE
SUB-OBJECTIVE
Noise
Environment

Increase in noise 0

Decrease in noise 51
Local Air Quality
Local air quality is poor particularly in close proximity to the A2 and A282. ‘Cleaner’ vehicles in the future are likely to contribute to an improvement in air
quality. Nevertheless anticipated improvement overall would be less with the Scheme when compared to Do-Minimum Scenario.
Greenhouse Gases
Overall CO2 emissions from the road network will increase slightly over the period 2007 to 2022 as a result of increased traffic flows. This broad assessment
does not take into account the likely benefits due to the reduction in congestion at the junction.
Landscape
Degraded urban fringe landscape, existing motorway/link road/junction screened by mounding and planting. ‘4 tier’ to Junction 2 visible.
Not applicable
Slight Adverse
Townscape
Not applicable
Not applicable
Not applicable
Heritage of Historic Resources
Deterioration to the setting of listed buildings and Scheduled Ancient Monument at Hawley Manor and reduction in the completeness of later prehistoric and
Roman remains.
Not applicable
Slight Adverse
Biodiversity
No direct impact on designated sites, but indirect effect on Darenth Wood SSSI, calcareous grassland, hedgerows of county significance and potential
disturbance to Dormouse habitat.
Not applicable
Moderate Adverse
th
No. of properties experiencing:
27 properties – Better air quality
64 properties – Worse air quality
Weighted property concentrations (opening
year):
PM10 +1780.2μg/m3
NO2 +2344.60μg/m3
Not applicable
Increase in greenhouse gases as a result of
the Scheme in Year 2022 of +5187
tonnes/year = +9.5%
Water
Soakaways relocated and/or replaced with balancing ponds. Enhanced pollution control facilities before discharging into river.
Not applicable
Slight Beneficial
Physical Fitness
No change to distances cycled or walked
Not applicable
Neutral
Journey Ambience
Less congestion and stress reduced due to improved signing
Not applicable
Slight Beneficial
Accidents
Improved junction layout to deal with peak-time queuing problem on A2 and M25 should improve safety.
(Figures include accidents saved in Kent Thameside and exclude accidents during maintenance and construction)
Accidents
-77
Deaths
0
Serious
-3
Slight
-103
Safety
Security
Proposed CCTV coverage at Junction 2
Not applicable
Transport Economic Efficiency
Provides positive benefits in both high and low growth forecasts
Public Accounts
PVB =£1.3m
(£0.8m if maintenance and
construction accidents
are included)
Slight beneficial
Central Govt PVC = £70.4m
Users PVB = £54.3m
TEE Bus users and Transport Providers
T’prt P’vders PVB = £2.4m
Economy
Accessibility
Integration
TEE consumers
Users PVB = £50.4m
Reliability
Scheme should improve reliability due to improved flow through M25 J2
Not applicable
Moderate beneficial
Wider Economic Impacts
Improve access from M25 and A2 to regeneration areas in Kent. Vital for the future development of Kent Thameside.
Serves designated regeneration area?
Development depends on scheme
Yes
No
Option Values
No effect
Not applicable
Neutral
Severance
Severance already caused by existing junction.
Not applicable
Neutral
Access to the Transport System
Benefits to existing network, increased opportunities for public transport initiatives not assessed.
Not applicable
Neutral
Transport Interchange
Forms integral part of public transport based strategy for Kent and Thameside development.
Not applicable
Moderate Beneficial
Land-use Policy
Some loss of good agricultural land which is against local and national policy objectives
Not applicable
Adverse
Other Government Policies
Direct and indirect effect on Green Belt, nature and heritage conservation designations which is contrary to local and national policy objectives
Not applicable
Adverse
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
127
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table D.2 – Appraisal Summary Table: A2/A282 Dartford Improvement (ECI Phase 2 with Link E deferral, Jan 2004) Changes highlighted
Appraisal Summary Table (REV 2) A2 / A282 Dartford Improvement
Option:
Description:
Problems: Junction needs improvement and A2 needs
widening to avoid peak period congestion
Present Value of Costs to Government
£102.2m (all costs are 2002 values
discounted to 2002)
QUALITATIVE IMPACTS
QUANTITATIVE ASSESSMENT
ASSESSMENT
No properties would experience an increase in noise levels in the Design Year (2022) due to use of low noise surfacing, mounds and fencing. 51 properties
would experience a reduction in noise levels of between 0.7 and 7.5 dB(A), 20 of which would experience a reduction greater than 3 dB(A). Without the
Scheme, use of low noise surfacing in the Design Year would mean 45 properties would experience a reduction of between 1 and 3dB (A).
No. of properties experiencing:
30 less people highly annoyed in 2022
Improvement comprising free flow links for E-N, N-E movements. Includes 3 multi-span viaducts and 4 further interchange bridges. Also includes 2km of A2
widening between M25 and Bean.
OBJECTIVE
SUB-OBJECTIVE
Noise
 Increase in noise 0
 Decrease in noise 51
Local Air Quality
Local air quality is poor particularly in close proximity to the A2 and A282. ‘Cleaner’ vehicles in the future are likely to contribute to an improvement in air
quality. Nevertheless anticipated improvement overall would be less with the Scheme when compared to Do-Minimum Scenario.
Greenhouse Gases
Overall CO2 emissions from the road network will increase slightly over the period 2007 to 2022 as a result of increased traffic flows. This broad assessment
does not take into account the likely benefits due to the reduction in congestion at the junction.
Traffic which would have previously used link E will now flow onto a temporary Link located on the existing roundabout, which does not result in traffic flow
change to any other road links. Therefore, the assessment score does not alter with Link E omitted from the scheme.
Not applicable
Increase in greenhouse gases as a result of
the Scheme in Year 2022 of +5187
tonnes/year = +9.5%
Landscape
Degraded urban fringe landscape, existing motorway/link road/junction screened by mounding and planting. ‘4th tier’ to Junction 2 visible.
Not applicable
Slight Adverse
Environment
No. of properties experiencing:
27 properties – Better air quality
64 properties – Worse air quality
Weighted property concentrations (opening
year):
PM10 +1780.2μg/m3
NO2 +2344.60μg/m3
Townscape
Not applicable
Not applicable
Not applicable
Heritage of Historic Resources
Deterioration to the setting of listed buildings and Scheduled Ancient Monument at Hawley Manor and reduction in the completeness of later prehistoric and
Roman remains.
Not applicable
Slight Adverse
Biodiversity
No direct impact on designated sites, but indirect effect on Darenth Wood SSSI, calcareous grassland, hedgerows of county significance and potential
disturbance to Dormouse habitat.
Not applicable
Moderate Adverse
Water
Soakaways relocated and/or replaced with balancing ponds. Enhanced pollution control facilities before discharging into river.
Not applicable
Slight Beneficial
Physical Fitness
No change to distances cycled or walked
Not applicable
Neutral
Journey Ambience
Less congestion and stress reduced due to improved signing
Not applicable
Slight Beneficial
Accidents
Improved junction layout to deal with peak-time queuing problem on A2 and M25 should improve safety.
(Figures include accidents saved in Kent Thameside and exclude accidents during maintenance and construction)
Accidents
Safety
Security
Proposed CCTV coverage at Junction 2
Not applicable
Transport Economic Efficiency
Provides positive benefits in both high and low growth forecasts
Public Accounts
-77
Deaths
0
Serious
-3
Slight
-103
PVB =£1.5m
(£0.9m if maintenance and
construction accidents
are included)
Slight beneficial
Central Govt PVC = £102.2m
Consumer Users PVB = £73.326m
TEE Bus users and Transport Providers
Private Sector P’vders PVB = £16.550m*
Economy
Accessibility
Integration
TEE consumers
Business Users PVB = £89.123m*
Reliability
Scheme should improve reliability due to improved flow through M25 J2
Not applicable
Moderate beneficial
Wider Economic Impacts
Improve access from M25 and A2 to regeneration areas in Kent. Vital for the future development of Kent Thameside.
Serves designated regeneration area?
Development depends on scheme
Yes
No
Option Values
No effect
Not applicable
Neutral
Severance
Severance already caused by existing junction.
Not applicable
Neutral
Access to the Transport System
Benefits to existing network, increased opportunities for public transport initiatives not assessed. Facilitates access to Ebbsfleet International Rail Station and
to regeneration areas
Not applicable
Neutral
Transport Interchange
Forms integral part of public transport based strategy for Kent and Thameside development.
Not applicable
Moderate Beneficial
Land-use Policy
Some loss of good agricultural land which is against local and national policy objectives
Not applicable
Adverse
Other Government Policies
Direct and indirect effect on Green Belt, nature and heritage conservation designations which is contrary to local and national policy objectives
Not applicable
Adverse
*These figures corrected from AST entries with apparent typos (Private sector providers - $16550m Business users £89123m)
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
128
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table D.3 – Appraisal Summary Table: M25 J1b – 3 widening (2006)
Appraisal Summary Table Date: 1/12/06. Stage 3 - Version IFU Rev 1
Option:
Description: Widening from three to four lanes in each direction between the south facing slip roads of M25 J2 and the north facing M20 link road
merge/diverge at J3. The southbound carriageway of M25 to be widened from two to three lanes between J1b and M25 J2 southbound slip road. Lighting
2
from J2 to J3. Additional land available for construction of vegetative treatment pond for surface water runoff. This land measures approximately 6000m and
is contiguous with the existing M25 Motorway Boundary
Problems: Unpredictability of travel times. Lack of orbital
routes around London. Need for access to Thames
Gateway regeneration area.
Present Value of Costs to Public
Accounts
QUALITATIVE IMPACTS
QUANTITATIVE ASSESSMENT
ASSESSMENT
Noise
Traffic flows on the Scheme would increase slightly resulting in an increase in annoyance for properties nearby. However, the introduction of environmental
barriers at Hawley Road result in an overall reduction in population annoyed by noise. Parkwood Hall School is more than 400m from the proposed road
alignment. It is not close enough to the Scheme for the noise change to have an effect on overall noise levels due to other existing roads dominating the
noise environment at this location. In the Do-minimum 146 people will be subject to noise levels in excess of 69 dB LA10,18hr whereas with the Scheme 108
would be exposed to noise levels in excess of 69 dB LA10,18hr. This is a reduction of 38 people.
Do-minimum (DM): est. 113 people likely to be annoyed by
traffic noise in the longer term. Do-something (DS): est.
105 people likely to be annoyed by traffic noise in the
longer term.
Net reduction in estimated population
annoyed: 8
Local Air Quality
Traffic flows would increase slightly. Properties adjacent to the section of M25 between J1b and 2 before slip roads show very slight improvements in air
quality due to speed changes. This area is within Dartford BC’s declared AQMA. Properties adjacent to the section of M25 before J2 slip roads and J3 show
no discernable change in air quality. Some of these properties fall within Sevenoaks DC’s declared AQMA.
Air quality would improve at 63 properties and deteriorate at
112 properties. Whilst an additional 3 properties (total 22)
would be exposed to NO2 levels in excess of the Air Quality
Objectives, contrary to PPS23, the change in concentration
would be indiscernible compared to current levels.
Greenhouse Gases
Overall increase in vehicle flows would result in a slight increase in CO2 emissions.
Landscape
1 Special Landscape Area and 2 Areas of Local Landscape Importance (ALLI) in the Study Area. Scheme would not detract from or be in conflict with
existing features and landscape character of the area, although tranquillity and land cover across the area would be slightly affected. Proposed lighting would
add to impact, with a change in night time landscape character from several visual receptors. Effects of lighting on the Kent Downs AONB would be slight as
currently lit J3 intervenes.
Slight adverse
Townscape
Although the Scheme would impact on housing at Hawley , in terms of views and increasing the dominance of major roads in the area, adverse impacts, this
would be offset by mitigation with the installation of environmental barriers.
Neutral
Heritage of Historic Resources
The scheme will have a negative impact on regionally important sites, but the actual extent of the impact is limited because of the width of the land take.
Slight adverse
Biodiversity
No impact on designated sites. The reduction in the width of the soft estate as a result of scheme widening would contribute to a loss of habitat for reptiles
and breeding birds however the biodiversity value of retained habitats would be enhanced through appropriate management.
Slight adverse
Water
Water features in the study area are typical of the locality with a major aquifer (Chalk) providing abstraction water and the River Darent crossing under the
M25. Provision of pollution control facilities, including spillage containment and oil interception at outfall locations, will result in improved pollution control
resulting in a benefit in terms of protecting groundwater quality.
Slight benefit
Physical Fitness
The health benefits would remain unchanged as there are no changes to the PROW network.
Neutral
Journey Ambience
The proposals are beneficial in terms of anticipated reduction in traffic congestion, improved road layout, signage and lighting. However this is balanced by
reduced lane width possibly causing increased fear of accidents.
Neutral
Accidents
Increase in accident rate on M25 J1b – 3 as a result of increase in traffic from widening is more than compensated for by reductions in traffic on local roads
from traffic reassignment to M25, resulting in monetary benefits and overall reductions in accidents.
PVB £0.934m low growth, £4.221m high
growth: average £2.58m.
Security
Would be slight benefit as CCTV is incorporated throughout M25 J1b to 3. Emergency call facilities would be improved compared to existing situation.
Slight positive
Public Accounts
PVC does not include the anticipated value engineering savings which are reflected in the current Forecast Outturn Scheme Cost Estimate.
PVC £66.828m low growth, £71.598m high
growth: average £69.213m.
Transport Economic Efficiency:
Bus.Users & Transport Providers
Scheme gives good value for money for business users.
PVB £75.507m low growth, £171.236m high
growth: average £123.4m.
Transport Economic Efficiency:
Consumers
Scheme gives good value for money for consumers.
PVB £51.239m low growth, £110.727m high
growth: average £81m
Reliability
Reliability benefits assessed using the stress-based approach described in TAG Unit 3.5.7. This measures the change in stress by calculating the ratio of
AADT to Congestion Reference Flow (CRF). Values of less than 0.75 indicate no stress to the road system. For the widening scheme, all reliability ratios are
less than 0.75, & are less than for the Do-Minimum.
This approach does not provide a direct quantification of
changes in reliability or reliability benefits.
Improved Journey Time Reliability
Wider Economic Impacts
Better journey time reliability would increase the labour pool for Kent Thames Side Regeneration Area. Average journey times between J1b and 3 would be
reduced by 30-60 sec in 2008 and by 40-300 sec by 2023 relative to the baseline. The strategic nature of Scheme means it would have beneficial impacts for
companies relying on distribution of goods, with wider benefits likely. It has been assumed in the quantitative analysis that only 10% of the jobs created in the
Regeneration Area would be attributable to the Scheme. Many firms in existing and future business parks are transport reliant (e.g. logistics firms) and
therefore improvements to highway capacity would be beneficial for their long-term future.
Up to 303 jobs in the RA directly influenced by 2018. Up to
99 jobs for residents of the RA
Up to 99 jobs for residents of the RA
Option Values
No options as part of scheme.
Neutral
Severance
5 footpaths run close to the proposed widening, and two cross over the M25, however none would be affected by the scheme.
Neutral
Access to the Transport System
Although access to public transport systems (e.g. Ebbsfleet train station) is improved, the Scheme does not form part of a public transport route.
Neutral
On-line widening to 4 lanes, with discontinuous
hard shoulders
OBJECTIVE
SUB-OBJECTIVE
Environment
Safety
Economy
Accessibility
DM: 91,739 t/annum CO2. DS: 95,129 t/annum CO2. 3.7%
increase in CO2 from traffic, compared with the DM
scenario.
Concentrations weighted for exposure:
NO2 : +209.73
PM10: +126.65
3,390 t/annum more CO2 compared with Dominimum
Transport Interchange
Not applicable as no interchange facilities available between Junction 1b to 3 of the M25.
Land-use Policy
Proposals consistent with most plans/polices at national and regional level, supporting reduction in traffic congestion. Local policy objectives for protection of
existing vegetation, habitat and heritage, and encouragement of limited lighting proposals not met by the Scheme, causing some adverse impacts.
Neutral
Other Government Policies
Some unavoidable impacts on environment set out in documents by ODPM (now DfCLG). However some policies supported, such as maintenance
of existing transport network capacity enhancement and improvements to key access routes to Kent Thameside.
Neutral
Integration
.
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
129
Neutral
£69m
Neutral
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table D.4 – Evaluation Summary Table A2/A282 Dartford Improvement
A2/A282 Dartford Improvement
OBJECTIVE
SUB-OBJECTIVE
QUALITATIVE IMPACTS
Environment
Noise
Overall traffic impacts within 10% of forecast range, hence noise impact assumed as forecast
As expected
Local Air Quality
Overall traffic impacts as expected hence noise impact assumed likewise, with no worsening in air quality in AQMAs.
As expected
Greenhouse Gases
Increased emissions due to traffic growth above forecast
Landscape
Mitigation generally implemented as expected but it is too soon to evaluate planting impact on landscape
As expected
Townscape
n/a
-
Heritage of Historic Resources
Slightly less impact due to deferral of Link E
As expected
Biodiversity
Mitigation seems to have been implemented as expected. Further information on success of species relocation needed in FYA
As expected
Water
Mitigation seems to have been implemented as expected.
As expected
Physical Fitness
Public rights of way are unaffected by the scheme and there is no new severance.
As expected
Journey Ambience
New gantries and signage have improved driver information. Provision of more lanes and new junction layouts have generally improved journey
times. Additional lighting will have improved night time driving conditions.
As expected
Accidents
Annual accident saving much better than expected
Security
CCTV installed
Transport Economic Efficiency
Positive benefits for users, even based on narrow corridor only.
Combined with M25 J1b- 3 scheme, BCR of 2.2 against forecast of 2.3
Reliability
Reduction in journey time variability
As expected
Wider Economic Impacts
Infrastructure provided to serve regeneration area. Recession means too early to assess impact on jobs
As expected
Option Values
No impact
-
As expected
Severance
No impact
-
As expected
Access to the Transport System
Access improvements to Ebbsfleet International Station, employment opportunities and retail for car users
-
Transport Interchange
-
As expected
Land-use Policy
Slightly less impact on heritage policy from omission of link E
As expected
Other Government Policies
-
As expected
Safety
Economy
Accessibility
Integration
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
QUANTITATIVE ASSESSMENT
1349 tonnes net increase (11%) in 2009
8 accidents saved
ASSESSMENT
As expected
Better than expected
As expected
130
£170m PVB TEE
As expected
Slightly better than expected
Post Opening Project Evaluation
A2 / A282 Dartford Improvement & M25 J1b – 3 Widening schemes: One Year After Study
Table D.5 – Evaluation Summary Table: M25 J1b – 3 widening
M25 J1b – 3 widening
OBJECTIVE
SUB-OBJECTIVE
QUALITATIVE IMPACTS
Environment
Noise
Traffic flows are lower than forecast (possibly due to recession impacts) and improved noise mitigation than originally planned
Better than expected
Local Air Quality
Traffic flows are lower than forecast (possibly due to recession impacts)
Better than expected
Greenhouse Gases
Safety
Economy
Accessibility
Integration
QUANTITATIVE ASSESSMENT
Increased emissions due to increased speeds, but as with appraisal, this does not fully consider the impact of reduced congestion
4% net increase, 727 tonnes in 2009
(over a narrower area than appraisal)
ASSESSMENT
As expected
Landscape
Mitigation generally implemented as expected but it is too soon to evaluate the success of the new landscape planting in screening and integration.
As expected
Townscape
Mitigation generally implemented as expected.
As expected
Heritage of Historic Resources
Impacts to settings of cultural heritage assets such as Listed Buildings and Swanley Conservation Area are considered to be minimal
As expected
Biodiversity
No impact on designated sites, as predicted, and mitigation largely implemented as predicted although planting has not yet matured.
As expected
Water
Improved water pollution control measures installed as expected. No monitoring data to confirm success
As expected
Physical Fitness
Negligible change to one footpath. No new severance
As expected
Journey Ambience
New gantries, improved signage, additional lighting all improve ambiance.
Accidents
Annual accident saving much better than expected
Security
CCTV installed
As expected
6 accidents saved, J2-3
Better than expected
As expected
Transport Economic Efficiency
Combined with A2/A282 scheme, BCR of 2.2 against forecast of 2.3
Reliability
Reduced journey time variation, especially J3-2 northbound
As expected
Wider Economic Impacts
Infrastructure provided to serve regeneration area. Recession means too early to assess impact on jobs
As expected
Option Values
No impact
-
As expected
Severance
No impact
-
As expected
Access to the Transport System
Access improvements to employment and retail for car users
-
Transport Interchange
-
As expected
Land-use Policy
-
As expected
Other Government Policies
-
As expected
5084038/POPE A2 A282 M25 J1b-3 OYA final jul 2011.docx
131
PVB £161m narrow area only TEE
As expected
Slightly better than expected