Buckingham Transport Model
Traffic Forecasting and Assumptions
August 2012
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22/08/2012
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Version 14 July 2012
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Transport for Buckinghamshire
Buckingham Transport Model
Traffic Forecasting and Assumptions
B1279862/TM03
BTM/TFAR
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Contents
1
1.1
1.2
1.3
Introduction
Purpose of Report
Buckingham Study Area
Structure of Report
1
1
1
2
2
2.1
2.2
2.3
Land Use Assumptions
Policy Background
Do-Minimum Development
Silverstone Masterplan
3
3
3
5
3
Transport Infrastructure Provision
6
4
4.1
4.2
4.3
4.4
4.5
Traffic Forecasting
Introduction
Overview of Modelling Methodology
Through-Trip and Trend-Based Growth Factors
Do-Minimum Development Trip Generation
Final Forecast Matrices
7
7
7
8
9
9
5
Summary
Table 2-A
10
Table 4-A
Table 4-B
Table 4-C
Do-Minimum Land Use Development – Housing and Mixed Use
Allocations
Do-Minimum Land Use Development – Employment Allocations
Transport Provision associated with Do-Minimum
Developments
Growth Factors for Background Growth and Through Trips
Peak Period Trip Generation from Developments
Total Trips for the Forecast Scenarios
6
8
9
9
Figure 1-A
Figure 2-A
Figure 4-A
Buckingham Study Area
Locations of Do-Minimum Land Use Development
Overview of Forecasting Methodology
1
5
7
Appendix A
Appendix B
Glossary
Do-Minimum Development Assumptions
Table 2-B
Table 3-A
4
4
1
Introduction
1.1
Purpose of Report
Jacobs was commissioned by Transport for Buckinghamshire (TfB) and Aylesbury
Vale District Council (AVDC) to develop a 2011 base year transport model which
reflects current traffic conditions, providing a platform from which future traffic levels
and patterns of movement can be assessed. Details of the base model development
are provided in the ‘Local Model Validation Report’ for the Buckingham Transport
Model dated June 2012.
This report describes the assumptions for future year land use and the traffic
forecasting methodology used to build a traffic model of Buckingham for 2031. The
scenario considered is the Do-Minimum scenario, which provides a basis to assess
the future performance of the Buckingham highway network and the impact of
potential changes in land use or transportation infrastructure.
1.2
Buckingham Study Area
Buckingham is located in the Aylesbury Vale District in Buckinghamshire, with a
current population around 12,000, with a larger community area of nearly 25,000
including surrounding villages. The town is situated approximately 13 miles west of
Milton Keynes and 17 miles north of Aylesbury. The strategic highway network
consists of the A413, A422 and A421 which provide north-south and east-west
connections to the rest of the County and major urban areas outside
Buckinghamshire. The study area for this assessment comprises the urban area of
Buckingham, and its approaches, as shown in Figure 1-A.
Contains Ordnance Survey data © Crown copyright and database right 2011
Figure 1-A
N
Buckingham Study Area
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
1
1.3
Structure of Report
The contents of the report are outlined below:
•
•
•
•
•
Section 1 – overview of the report purpose and background information
Section 2 – description of assumptions regarding housing and employment land
use
Section 3 – description of assumed changes to transport provision
Section 4 – description of traffic forecasting methodology including traffic growth
factors
Section 5 – summary of the report
A glossary of terms is presented in Appendix A.
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
2
2
Land Use Assumptions
2.1
Policy Background
The Aylesbury Vale District Local Plan (AVDLP) was adopted in January 2004. The
Local Plan forms part of the Development Plan and presents AVDC’s policies and
proposals for the use of land and buildings.
The development strategy defined in the Local Plan provides for 200 houses at a
site off Moreton Road to the north of Buckingham, an employment development
within and adjacent to Buckingham Industrial Park and two sites for retail and mixed
use development. The original timetable for completion of these developments
covered a period up to 2011.
The commitments identified are now nearing completion, or are under way. Further
developments have been granted planning permission including the ‘Hallam Land’
site consisting of 700 houses and 8,600sqm of employment at a major greenfield
site off London Road to the south of the A421.
2.2
Do-Minimum Development
This section establishes the Do-Minimum land use development in Buckingham.
The information on sites that will deliver housing is taken from AVDC’s position
statement on District Housing Land Supply (September 2011) and consultation with
AVDC. The current supply of housing land is made up of:
•
•
Sites with planning permission
Sites that do not yet have planning permission, but have been approved in
principle, subject to the completion of a Section 106 or planning obligation
agreement
The full list of housing and mixed-use developments is presented in Table 2-A, with
other land use types (e.g. employment and retail-led sites) shown in Table 2-B. A
plan of these developments is shown in Figure 2-A, and the full list is included in
Appendix B. All assumptions have been agreed in consultation with AVDC. The
latest AVDC projection of completion rates forecasts these developments being fully
built out by 2031. The Coalition Government Localism Agenda will inform the future
location and quantum of growth beyond existing committed developments.
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
3
No. of
Dwellings
constructed
to 2011
No. of
Dwellings
to be
constructed
to 2031
ID
Reference (Local
Plan/ Planning
Location
Application)
1
09/01035/AOP
London Road site, south of A421
2
06/01809/AOP
Moreton Road
3
07/01003/AOP
Bridge Street
4
06/03332/AOP
Tingewick Road
93
Market Hill
61
5
700
118
82
103
Total
1,039
Table 2-A
Do-Minimum Land Use Development – Housing and Mixed Use Allocations
Note: Table includes sites with dwellings completed in 2011, for completeness.
In addition to the developments presented in Table 2-A, there are also a number of
smaller development sites of less than 5 dwellings providing an additional 35
dwellings. In summary it is forecast that there are 1,074 (1,039 + 35) dwellings to be
constructed by 2031.
Table 2-B presents a list of assumed employment-led developments. The Tingewick
Road housing development would involve the loss of existing employment floor
space.
ID
Reference (Local
Plan/ Planning
Location
Application)
1
09/01035/AOP
London Road site, south of A421
3
07/01003/AOP
Bridge Street
4
06/03332/AOP
Tingewick Road
6
10/00360/APP
Tesco Store Extension, London Road
Total
Table 2-B
Business
Land Use
(GFA)*
Retail and
Other Land
Use (GFA)*
8,600
1,400
216
2,046 (B1)
-12,395 (B8)
2,490
-1,749
4,106
Do-Minimum Land Use Development – Employment Allocations
Note: * GFA presented in units of sqm
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
4
Key
London Road site,
south of A421
Bridge Street
Tingewick Road
Tesco Extension,
London Road
Market Hill
Figure 2-A
2.3
Locations of Do-Minimum Land Use Development
Silverstone Masterplan
Silverstone is approximately 6 miles to the north of Buckingham and will be a
significant trip attractor in the area. Phase 1 of the Silverstone Masterplan, which
comprises about 25% of the whole development vision, has been awarded planning
approval subject to the completion of a Section 106 agreement. For the purposes of
the development of the Do-Minimum models it is assumed that only Phase 1 will be
completed by 2031. Phase 1 comprises:
•
•
•
Business Park
Education Campus
One Hotel
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
5
3
Transport Infrastructure Provision
The majority of the Do-Minimum developments described in Section 2 will be
delivered without the need for significant new highway infrastructure. However, the
larger development off London Road to the south of the A421 will involve the
construction of new access junctions. A list of new transport infrastructure assumed
in the forecast modelling is presented in Table 3-A. Any provision associated with
Do-Minimum development that is already constructed forms part of the ‘baseline’
infrastructure, and hence is excluded from this table.
ID
Development
Assumed provision associated with Do-Minimum
developments
Additional arm on the London Road / Tesco access
roundabout
1
London Road site, south of
A421
Additional 3-arm roundabout 180m south of the Tesco
roundabout
Enlargement of London Road / A421 roundabout
2
Moreton Road
Reduce speed limit from 40mph to 30mph
-
N/A
Pedestrian crossing on London Road connecting Meadway
and Hare Close pedestrian route
Table 3-A
Transport Provision associated with Do-Minimum Developments
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
6
4
Traffic Forecasting
4.1
Introduction
This section describes the traffic forecasting methodology for the development of the
2031 Do-Minimum scenarios. The forecasting process utilises the land use and
transport infrastructure assumptions described in Sections 2 and 3.
4.2
Overview of Modelling Methodology
The Buckingham Transport Model provides an accurate baseline in terms of traffic
volumes, journey times, and general congestion and is an appropriate base upon
which to apply traffic growth forecasts. The Buckingham Transport Model is
validated to a 2011 base year and reflects typical morning (08:00 – 09:00) and
evening (17:00 – 18:00) peak traffic conditions. Further detail on the 2011 base year
model may be viewed in the ‘Local Model Validation Report’ for the Buckingham
Transport Model, dated June 2012.
The approach to establishing forecast scenarios takes the 2011 scenario as the
baseline and translates the trend, land use, and transport infrastructure assumptions
into a set of traffic growth assumptions. Figure 4-A presents an overview of the
forecasting methodology.
Figure 4-A
Overview of Forecasting Methodology
First, a set of traffic growth factors are derived from the TEMPRO database.
TEMPRO is a software package created by the Department for Transport (DfT),
which provides forecast data on trips for transport planning purposes. The version of
the software used in this assessment (version 6.2 with dataset version 6.2) provides
multi-modal trip data for the years 1991 to 2041. Outputs are given in terms of
growth factors between the selected base and forecast years or as raw trip-end
data.
TEMPRO provides two elements of the traffic growth forecast in this approach.
Firstly, factors are derived for longer distance (external – external) through-trips
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
7
which are not directly associated with land use in Buckingham and will take into
account growth in neighbouring areas such as Milton Keynes and Bicester.
Secondly, the TEMPRO database provides a trend-based traffic growth factor
related to socio-demographic changes in Buckingham. The second growth factor
affects only those trips with an origin and/or a destination within Buckingham. Each
of these growth factors is further adjusted by the application of a fuel price and
income adjustment factor which is appropriate for transport models with fixed trip
matrices.
Next, traffic growth levels associated with the Do-Minimum land use assumptions
are established. Whilst the TEMPRO software provides factors to reflect both sociodemographic trends and policy-based growth related to land use, the zones within
TEMPRO are large, and as a result the analysis is coarse. As such, the application
of broad growth factors is considered to be inappropriate to assess accurately the
impact of land use changes i.e. for individual developments. It is important to ensure
that trips associated with each development are localised on the network in the
appropriate area, as opposed to being distributed over the entire study area.
TEMPRO policy-based land use factors for the trips internal to Buckingham are
therefore not applied. Instead, trip generation estimates for each Do-Minimum
development were either obtained from the Transport Assessment for planning
application or from the TRICS database. The methodology ensures there is no
‘double-counting’ of trips from new land use development.
The Silverstone Masterplan development is not explicitly included in TEMPRO. To
take into account trips generated by the development affecting Buckingham, trips
arising from Phase 1 of the development that would use the A413 or A421 through
Buckingham were added into the matrices.
4.3
Through-Trip and Trend-Based Growth Factors
The growth factors for through trips and trend-based socio-demographic changes
are presented in Table 4-A, and include adjustments to reflect changes in fuel price
and income.
Factor applied to 2011 trips
Factor
AM
PM
1.294
1.306
1.043
1.022
External Through-Trips
2011 - 2031
Internal Trend-Based Growth
2011 - 2031
Table 4-A
Growth Factors for Background Growth and Through Trips
The factors for external through-trips were determined from TEMPRO (Dataset 6.2),
based upon the growth rate for Buckinghamshire between the base year 2011 and
the forecast year 2031, using the default housing and employment assumptions
included in TEMPRO. The factors for internal trend-based growth were derived from
the same dataset, based upon the growth rate for Buckingham Town.
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
8
4.4
Do-Minimum Development Trip Generation
The assumptions defined in the future land use were translated into estimates of trip
generation using trip rates agreed in the associated Transport Assessment or from
the TRICS database. Table 4-B summarises the total peak period trip generation for
the Do-Minimum developments.
AM Peak Trips
Development
Destinations
Origins
Destinations
635
441
512
637
Do-Minimum Developments
Table 4-B
PM Peak Trips
Origins
Peak Period Trip Generation from Developments
Where TRICS has been used to estimate the trip generation, the average trip rates
(not 85th percentile) were used to generate the trips in order to take account of the
implementation of appropriate travel planning measures associated with the
particular development to manage and limit the growth of vehicular trip making.
4.5
Final Forecast Matrices
Table 4-C presents the total vehicular trips generated by the modelling process for
the 2031 Do-Minimum scenarios.
Scenario
AM (08:00 – 09:00)
PM (17:00 – 18:00)
Total Highway
Trips
% Growth
Total Highway
Trips
% Growth
2011 Base
7096
-
6929
-
2031 Do-Minimum
8916
25.65
8650
24.84
Table 4-C
Total Trips for the Forecast Scenarios
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
9
5
Summary
Jacobs was commissioned by TfB and AVDC to develop the Buckingham Transport
Model to provide a robust modelling platform from which to meet the future transport
assessment needs of TfB and AVDC. This report describes the traffic forecasting
work that was necessary to establish future year Do-Minimum land use scenarios.
These scenarios provide a means to assess the performance of the Buckingham
highway network in future and the impact of potential changes in land use and
transportation infrastructure.
The Aylesbury Vale District Local Plan (AVDLP) was adopted in January 2004. The
Local Plan forms part of the Development Plan and presents AVDC’s policies and
proposals for the use of land and buildings. This report establishes the Do-Minimum
land use development in Aylesbury. The information contained within this report for
housing developments is taken from AVDC’s position statement on District Housing
Land Supply (September 2011). Assumptions on the location of employment and
retail-led developments have been agreed with AVDC.
This process has established a set of assumptions which in turn inform a number of
traffic growth factors and trip generation estimates. This data is used to establish the
2031 Do-Minimum traffic scenarios which provide a suitable forecast for the
assessment of potential changes in land use and transportation infrastructure.
Buckingham Transport Model - Traffic Forecasting and Assumptions - Final.doc
10
Appendix A
Glossary
Term
Description
AVDC
Aylesbury Vale District Council
AVDLP
Aylesbury Vale District Local Plan
Capacity
The ability of a highway link or junction to carry or accommodate traffic flow
DfT
Department for Transport
GFA
Gross Floor Area
NTEM
National Trip End Model – provides a set of predictions of growth in car ownership
and car traffic, with associated planning data projections, at any geographical level
down to local authority districts. It forms part of the same forecasting system as the
1997 National Road Traffic Forecasts (NRTF97)
TEMPRO
Trip End Model Presentation Program – is a modelling tool designed to allow users to
look at the growth in trip ends, using actual and forecast data supplied by the
Department for Transport
TfB
Transport for Buckinghamshire - The Alliance between Buckinghamshire County
Council (BCC) and Ringway Jacobs established for the delivery of all transportation
services across the County
TRICS
Trip Rate Information Computer System – An interactive computer program (and
website) designed to calculate the likely rate or arrivals at and departures from a
development
Appendix B
No.
Do-Minimum Development Assumptions
Development/Location
Dwellings
Constructed
(to 2011)
Dwellings
(to be
constructed)
1
London Road site, south of
A421
2
Moreton Road
3
Bridge Street
103
4
Tingewick Road
93
5
Market Hill
61
6
Tesco Store Extension,
London Road
-
Sites less than 5 dwellings
Total
700
118
Business Type and GFA
B1 (8,600sqm), Doctors
Surgery (1,400sqm)
82
Café (129sqm), Retail
(87sqm)
B1 (2,046sqm), loss of
B8 (12,395sqm)
A1 (2,490sqm)
35
118
1074
Trip Rate
Source
AM
Origins
AM
Destinations
PM
Origins
PM
Destinations
TA
368
221
223
305
TA
118
40
48
106
TA
31
24
19
28
TRICS
25
34
40
29
TRICS
23
14
16
22
TRICS/TA
70
108
166
147
-
-
-
-
-
635
441
512
637