Tamaki Drive / Ngapipi Road Safety Improvement
Project
AUCKLAND TRANSPORT
Traffic Assessment Report
12 July 2016
312-13-674-PS
Tr af
f ic Ass
ssm
ent
Re
por
AU
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De
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Document history and status
Revision
Date
Description
By
Review
Draf t
27/05/2019
Draf t f or Discussion
Andrew Lawson
Sam Corbett
28/06/2016
Draf t f or Discussion
Andrew Lawson
Sam Corbett
12/07/2016
Final
Andrew Lawseon
Sam Corbett
Final
Approved
Distribution of copies
Revision
Issue
approved
Date issued
Issued to
Com ments
Traffic Assessment Report
Tamaki Drive - Ngapipi Road Safety Improvement Project
Project No:
IZ01489
Document Title:
Traffic Assessment Report
Revision:
Draft
Date:
12 July 2016
Client Name:
AUCKLAND TRANSPORT
Client No:
312-13-674-PS
Project Manager:
Thomas Small
Author:
Andrew Lawson
File Name:
I:\ZBIFA\Projects\ZB01489\DELIVERAB LES\Reports\Lodgement May 2016\Specialist
Reports\Traffic\Tamaki Drive Traffic AEE Report_V10_210616 post legal review addressedKW.docx
Jacobs New Zealand Limited
www.jacobs.com
© Copy right 2016 Jacobs New Zealand Limited. The concepts and inf ormation contained in this document are the property of Jacobs. Use or
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Limitation: This report has been prepared on behalf of , and f or the exclusiv e use of Jacobs’ Client, and is subject to, and issued in accordance with, the
prov isions of the contract between Jacobs and the Client. Jacobs accepts no liability or responsibility whatsoev er f or, or in respect of , any use of , or reliance
upon, this report by any third party .
i
Traffic Assessment Report
Contents
1.
Introduction .................................................................................................................................... 6
2.
Project Description ......................................................................................................................... 8
3.
2.1
Background .............................................................................................................................. 8
2.2
Options Considered .................................................................................................................. 8
Existing Environment ....................................................................................................................10
3.1
Existing Road Layout ...............................................................................................................10
3.2
Road Classification ..................................................................................................................10
3.3
Existing Traffic Flows ...............................................................................................................12
3.4
3.3.1
Hourly Flows on Tamaki Drive ...........................................................................................12
3.3.2
Turning flows at the Tamaki Drive / Ngapipi Road Int ersection .............................................13
Existing Road Conditions ..........................................................................................................13
3.4.1
SIDRA Model ...................................................................................................................13
3.4.2
Existing Queues ...............................................................................................................14
3.4.3
Results of Intersection Modelling .......................................................................................14
3.4.4
Rout e Security and Trip Reliability .....................................................................................15
3.4.5
Road Conditions on Alternative Routes ..............................................................................15
3.4.6
Side Roads ......................................................................................................................16
3.4.7
Geometry and Operation...................................................................................................16
3.5
Cras h Performance ..................................................................................................................16
3.6
Parking Provision .....................................................................................................................20
3.7
Walking and Cycling.................................................................................................................20
3.8
3.7.1
Pedestrian and Cyclist Facilities ........................................................................................20
3.7.2
Demand ...........................................................................................................................22
Public Trans port Network .........................................................................................................23
4.
The Proposed De sign ....................................................................................................................24
5.
Project Shaping .............................................................................................................................27
6.
Asse ssment of Effects...................................................................................................................28
6.1
Modelling of the Detailed Design Layout ....................................................................................28
6.2
Forec ast Flows used for Modelling ............................................................................................28
6.3
Modelled Intersection Performance ...........................................................................................28
6.4
Cras h Performance ..................................................................................................................30
6.5
Walking and Cycling.................................................................................................................30
6.6
Geometry ................................................................................................................................31
6.7
Rout e Security and Trip Reliability.............................................................................................31
6.8
Provision for Over-Dimension Vehicles ......................................................................................32
6.9
Parking....................................................................................................................................32
6.10
Travel Demand Management ....................................................................................................32
6.11
Emergency Vehicle Access ......................................................................................................32
6.12
Public Trans port .......................................................................................................................32
6.13
Construction Effects .................................................................................................................32
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Traffic Assessment Report
7.
Measure s to Avoid, Remedy or Mitigate Effects ............................................................................35
8.
Conclusions and Recommendations.............................................................................................35
Appendix A. Scheme Assessment Layout – Preferred Option 1
Appendix B. Traffic flows on Tamaki Drive between Solent Street and the Ngapipi Estuary Bridge
Appendix C. SIDRA Modelling Report
Appendix D. Results of the CAS Crash Analysis
Appendix E. Construction Sequencing
LIST OF FIGURES
FIGURE 1-1: LOCATION PLAN
6
FIGURE 3-1: EXISTING ROAD LAYOUT
10
FIGURE 3-2: ROAD HIERARCHY [C AN YOU IMPRO VE THE Q UALITY OF THIS MAP? HARD TO READ.]
11
FIGURE 3-3: PROPOSED AUCKLAND CYCLE NETWORK MAP [AGAIN QUALITY OF MAP NOT GREAT]
12
FIGURE 3-4: EXISTING INTERSECTION MODELS - LEVEL OF SERVICE OUTPUTS [MATCH COLOURS ON THE DIAGRAM TO THE
KEY?]
15
FIGURE 3-5: ALTERNATIVE ROUTES
16
FIGURE 3-6: CRASH DIAGRAM
18
FIGURE 3-7: MODES HIT BY RIGHT TURNING VEHICLES WHICH FAILED TO GIVE WAY (TOTAL OF 11 RIGHT TURN CRASHES)
20
FIGURE 3-8: PEDESTRI AN AND CYCLIST FACILITIES
21
FIGURE 3-9: CYCLIST APPROACHING VARI ABLE MESSAGE WARNING SIGN (INSTALLED IN 2010)
22
FIGURE 4-1: PROPOSED DESIGN
25
FIGURE 6-1: SIGNAL PHASING
28
FIGURE 6-2: SIGNALISED INTERSECTION MODELS - LEVEL OF SERVICE OUTPUTS
29
LIST OF TABLES
TABLE 3-1: EXISTING INTERSECTION FLOWS (AVERAGE W EEKDAY COUNTS; NO VEMBER 2015)
13
TABLE 3-2: EXISTING MAXIMUM QUEUE LENGTHS
14
TABLE 3-3: CRASH O VERVIEW BY YEAR AND CRASH SEVERITY
19
TABLE 3-4: EXISTING CYCLE COUNTS (CYCLES PER HO UR)
22
TABLE 6-1: AVERAGE INTERSECTION DELAY O UTPUTS FROM INTERSECTION MODELLING
29
TABLE 6-2: INTERSECTION APPROACH 95%ILE QUEUE LENGTHS OUTPUTS FROM INTERSECTION MODELLING (EXCLUDING
PHASE D)
29
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Traffic Assessment Report
Executive Summary
This traffic assessment for the Tamaki Drive Ngapipi Road Safety Improvement Project (the ‘Project’) describes
the existing environment and the expected traffic and transportation effects of the Project. The assessment is
based on the detailed design drawings which can be found in Appendix A of the Assessment of Environmental
Effects (AEE) Report, and background data which has been gathered on the existing operation including traffic
flows, bus operations, pedestrian and cycle movements, driver behaviour and crash history. Effects have been
considered both during construction and also when the improvements have been completed. This assessment
also outlines a brief history of how the Project has been shaped and refers to previous work. The project has
two key objectives:
a) Improvement of cyclist, pedestrian and motorist safety through the intersection.
b) Timely development of the intersection so that the duration of current safety issues is minimised.
Tamaki Drive west of the intersection typically carries just over 30,000 vehicles per day, as it serves as a key
connection from the eastern suburbs to the central city. The route is also popular for cyclists and pedestrians,
for commuting and leisure. The flows are highly tidal with high westbound flows towards the CBD in the AM
peak period and high eastbound flows towards the eastern suburbs in the PM peak period. Currently, the
intersection performs poorly, with some movements operating at capacity. There is heavy queuing in both the
AM and PM peak periods. ‘Reverse priority’ occurs during the AM peak when westbound traffic on Tamaki Drive
gives way to vehicles turning right into Ngapipi Road due to heavy traffic heading west on Tamaki Drive and this
has been accounted for in our assessment.
Besides the capacity issues for vehicle traffic, there are also identified concerns around the provision of facilities
for cyclists and pedestrians. The reported crash history over five year period 2011-2015 shows that cyclists are
significantly overrepresented in crashes. There were nine reported crashes involving cyclist s as 43% of the total
crashes, and cyclists were involved in eight of the thirteen minor or serious injury crashes. In particular, the
statistics show there is an apparent pattern of crashes related to motorists failing to give way to oncoming
cyclists when turning right into Ngapipi Road, even with the “cyclist approaching when flashing” variable
message sign installed in 2010.
Currently there is a shared use path along the northern side of Tamaki Drive and footpaths along Ngapipi Road,
but there are no pedestrian crossing facilities at the intersection, with only an uncontrolled refuge island on
Tamaki Drive 60m east of Ngapipi Road.
On street parking provision is limited in the intersection vicinity, and it is noted that these free unrestricted
parking spaces appear to be used informally for ‘park and ride’. There are a number of bus services using the
intersection and two pairs of stops within 100m (to the east and south of the intersection). However, these bus
stops are considered to be relatively infrequently used.
To address the existing cycle crash problem, a number of options have been considered by the various
assessments that have been undertaken over the past five years. Roundabout options were considered but
were ultimately eliminated from further consideration due to concerns about their ability to adequately provide
for the safety of pedestrians and cyclists. For this reason signalisation options were preferred.
The proposed design involves signalisation of the intersection. To provide adequate capacity, an additional left
turn lane has been provided for the Ngapipi Road approach and two lanes have been provided for the Tamaki
Drive east approach. Pedestrian and cyclist provisions include crossing facilities for all approaches, cycle lanes,
shared pedestrian cycle paths and advance stop boxes for cyclists. These works are expected to have an
overall significant positive impact on cyclist and pedestrian safety and movement, greatly improving the amenity
and efficiency for active modes.
Intersection modelling indicates that the net impact of signalisation is expected to result in an overall slight
increase in travel times. Average intersection delay increases in the AM peak (from 110 seconds to 134
seconds), reduces in the PM peak (from 60 seconds to 26 seconds) and increases in the low volume periods
(from 3 seconds to 17 seconds).
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Traffic Assessment Report
There are expected to be minimal permanent impacts on car parking, with approximately 13 spaces along
Tamaki Drive permanently removed as a result of the Project.
Impacts on bus patrons will also be minimal with the eastbound bus stop on Tamaki Drive being permanently
relocated 40m eastwards.
During construction, traffic, pedestrian and cycle movements will at times be impacted. The main impacts are
expected to be due to temporary partial lane closures or narrowing of the carriageway. The two pairs of bus
stops (on Tamaki Drive and Ngapipi Road) are likely to be temporarily relocated further east along Tamaki Drive
and south along Ngapipi Road. Some existing car parks or road reserve space may be closed for construction
vehicles and plant, and for temporary traffic management. A Traffic Management Plan (TMP) will required as a
condition of consent and will be written to manage traffic during construction to ensure any impacts from the
construction works on the transport network are minimised.
There are no property accesses within 400m and no side roads within 700m, and so any impacts on property
accesses are expected to be less than minor, both permanently and during construction works. Overall, the
Project is expected to greatly enhance amenity and safety for pedestrians and cyclists. While travel times may
at times be slightly longer for motorists, the Project promotes a shift to active modes, whilst having minimal
traffic impacts.
5
Traffic Assessment Report
1. Introduction
Auckland Transport is lodging resource consent applications to undertake safety improvements at the Tamaki
Drive / Ngapipi Road intersection in Auckland City. The safety improvements essentially signalise the current
priority controlled intersection.
The location of the proposed works is shown in the below diagram.
Figure 1-1: Location Plan
This report provides a traffic and transport assessment of the potential effects of the Tamaki Drive – Ngapipi
Road Intersection Improvements Project (“the Project”) and will be used to inform the full AEE for the Project. It
describes both the positive and negative traffic and transportation effects and also describes how negative
effects will be avoided, remedied or mitigated.
The traffic and transport assessment is fully integrated in that it provides a full multi-modal consideration.
The report is part of a suite of documents that together describe the actual and potential environmental effects
of the Project.
The Project has two key objectives:
a)
Improvement of cyclist, pedestrian and motorist safety through the intersection.
b)
Timely development of the intersection so that the duration of current safety issues is minimised.
The design drawings for the proposed improvements, referred to as the “proposed design” can be found in
Appendix A of the AEE Report.
This report has been prepared for the sole purpose of supporting Auckland Transport’s resource consent
application for the Tamaki Drive / Ngapipi Road Safety Improvement Project (the Project) in accordance wi th the
6
Traffic Assessment Report
scope of services set out in the contract between Jacobs and Auck land Transport (‘the Client’). Jacobs
accepts no liability or responsibility for, or in respect of, any use of, or reliance upon this report (or any part of it)
for any other purpose in any other context.
In preparing this report, Jacobs has relied upon, and presumed accurate, information, including earlier project
design reports, traffic and crash data, and road network information. If this information is determined to be
false, inaccurate or incomplete, or if the Project is altered then it is possible that our observations and
conclusions as expressed in this report may change.
This report may also describe specific limitations and/or uncertainties which qualify its findings. Acco rdingly, this
report should be read in full and no excerpts are to be taken as representative of the findings unless any such
excerpt and the context in which it is intended to be used have been approved by Jacobs in writing.
7
Traffic Assessment Report
2. Project Description
2.1
Background
An overview of the Project, including its history, the physical environment, context and objectives is outlined in
the AEE Report for the Project.
The site is an existing priority controlled T-intersection between Ngapipi Road and Tamaki Drive, in Orakei,
Auckland. The Project is primarily driven by safety concerns for motor vehicle users and cyclists using Tamaki
Drive. These concerns are supported by the crash history indicating a high rate of crashes for both modes.
Cyclists in particular are vulnerable to vehicle turning movements. The extent of the safety issues was
highlighted within a list of the Top 100 High Risk Intersections which was produced by NZTA based on crash
data collected from the NZ Transport Agency Crash Analysis System (CAS) crash database over the 10 year
th
period between 2003 and 2012. The intersection was ranked 10 within the list.
2.2
Options Considered
Over the past 15 years, options for upgrading the intersection have been examined in three major studies.
In 2000 a report was produced by URS. 1 In this study, options examined included bridge widening combined
with signalising the Tamaki Drive / Ngapipi Road intersection.
In 2011 a Project Feasibility Study (PFR)2 was undertaken by MWH. This study again looked at the bridge
widening option examined previously by URS, and also looked at roundabout and traffic signals options which
didn’t involve bridge widening. The study eliminated the bridge widening option due to its high cost. Considering
the two options which didn’t involve bridge widening (named in the report as the “Roundabout Option 2” and
“Traffic Signals Option 3”) the report stated:
“In conclusion, both options are economically viable. However when the lik ely impacts of Option 2 and Option 3
were considered along with the safety benefits that each provides, the Traffic Signals Option 3 is preferred on
the basis that it meets the project objectives of addressing safety concerns for pedestrians and cyclists at
Tamak i Drive and Ngapipi Road intersection and balances the safety needs for all road users along Tamak i
Drive by removing conflict and preventing crashes and injuries.”
In 2013 a Scheme Assessment Report (SAR)3 was produced by MWH. The report examined a wide range of
roundabout and traffic signals layouts. These included:

Option 1 - signalised T intersection with two lane slip lane left (signalised) from Ngapipi Road. Signalised
pedestrian crossings on all legs;

Option 2 - signalised T intersection without a slip lane. Signalised pedestrian crossings on all legs;

Option 3 - signalised T intersection with priority changed to the Tamaki Drive west / Ngapipi Road route.
The Tamaki Drive east leg ‘teed’ into the priority route;

Option 4 - single lane circulating roundabout with an uncontrolled left slip lane from Ngapipi Road to
Tamaki Drive;

Option 5 - single lane circulating roundabout with ‘Give Way’ controls on all legs .
These options were comparatively evaluated using a multi-criteria analysis (MCA) framework that scored the
options against the following criteria and weightings:

Cycling on-road (10)

Pedestrian Corridor (10)
1
2
3
URS (2000) Summary of Options, Tamaki/Ngapipi Intersection Widening
MWH (2011) Tamaki Drive / Ngapipi Road Intersection Improvements Project Feasibility Report
MWH (2013) Ngapipi Road / Tamaki Drive Intersection Improvements Scheme Report
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Traffic Assessment Report

Tamaki Drive as a destination (10)

Motor vehicles (9.5)

Cycling off-road (8.5)

Public transport corridor (8)

Intersection capacity / efficiency (6)

Future proof the footprint (5)
The MCA results preferred all signalised options over the roundabout options, in the order of Options 2, 3 then
1, primarily differentiated on the basis of pedestrian level of service and safety.
SIDRA modelling was also undertaken on the existing layout and all opt ions to assess their efficiency as
indicated by delay and queuing. This analysis was undertaken using existing flows. The existing AM peak model
was verified by modifying the gap acceptance parameters using observed queue lengths and travel speeds.
This was done to reflect observed ‘reverse priority’ during the AM peak with westbound traffic on Tamaki Drive
giving way to vehicles turning right into Ngapipi Road due to heavy traffic heading west on Tamaki Drive.
SIDRA analysis showed that Options 2, 3 and 5 resulted in unacceptable delays and / or queue lengths that
would adversely impact the road network, so these were rejected. Option 1 indicated the best capacity.
Option 1 was also assessed against the Tamaki Drive Masterplan (TDMP) and found to support three of the six
‘moves’ which support the vision in the TDMP 4. Option 1 was therefore overall deemed the preferred option.
This preferred scheme assessment option, Option 1 (a copy of which is provided in Appendix A to this report),
was then taken forward to the detailed design stage and is the subject of the current Resource Consent
application.
4
Auckland Council, Tamaki Drive Master Plan, “Six key moves to get us there”. Retrieved online May 2016.
http://www.aucklandcouncil.govt.nz/EN/AboutCouncil/representativesbodies/LocalBoards/Ora keilocalboard/Documents/tamakidrivemasterplanfinal
olbpart2.pdf
9
Traffic Assessment Report
3. Existing Environment
3.1
Existing Road Layout
The existing road layout is shown in Figure 3-1.
Figure 3-1: Existing Road Layout 5
The intersection is currently priority controlled with the Tamaki Drive (east-bound) having separate through and
right turn lanes, the Tamaki Drive (west-bound) approach having a single combined through and left lane, and
the Ngapipi Road approach having a left turn slip lane and a separate right turn lane. There is a marked flush
median on Tamaki Drive (east) which continues in varying width east to assist with turning movements and
separation of opposing directions. A westbound cycle lane is provided along Tamaki Drive and eastbound
cyclists are provided for on the shared path on the northern side of Tamaki Drive.
Around 150m east of the intersection a westbound transit T2 / bus lane merges with a general traffic lane. The
posted speed limit on both Tamaki Drive and Ngapipi Road is 50km/h.
Urban Route 6 extends along Tamaki Drive (west) and Ngapipi Road, and Urban Route 7 extends along Tamaki
Drive (east). These reinforce the roads’ function as key transport arterials.
3.2
Road Classification
The road hierarchy for Auckland City is shown in Figure 3-2.
5
Aerial imagery was retrieved from Google Earth Pro, Google 2016. Imagery of the site is dated 21 May 2012. Reproduced on basis of fu ll attribution.
10
Traffic Assessment Report
Tamaki
Ngapipi
intersection
Figure 3-2: Road Hierarchy6
Within the road network, defined by Auckland Transport, Tamaki Drive west of Ngapipi Road and Ngapipi Road
are classified as primary arterials, and Tamaki Drive east of Ngapipi Road is a secondary arterial. An overdimension vehicle route extends along both Ngapipi Road and Tamaki Drive west of Ngapipi Road.
Cycleways within Auckland City that are being delivered using Urban Cycleways Funding are shown in Figure
3-3.
6
Auckland Transport, ATCOP Chapter 4, Road Classification
11
Traffic Assessment Report
Tamaki
Ngapipi
intersection
Glen Innes to
Tamaki Shared Path
Figure 3-3: Proposed Auckland Cycle Network Map 7
Within the cycle network, Tamaki Drive is defined by Auckland Trans port as an existing cycleway. Ngapipi Road
is defined as a planned cycleway beyond 2018.
The Glen Innes to Tamaki Drive shared path is due to be constructed in 2018. This path may slightly reduce
cycle flows through the Tamaki Drive / Ngapipi Road intersection as it will provide an alternative route for
cyclists to use to reach the eastern suburbs.
3.3
Existing Traffic Flows
3.3.1
Hourly Flows on Tamaki Drive
Tamaki Drive west of Ngapipi Road currently carries weekday flows of just over 30,000 vehicles per day. These
flows split almost equally at the Tamaki Drive / Ngapipi Road intersection between vehicles turning right into
Ngapipi Road and vehicles proceeding along Tamaki Drive (east).
Traffic count data on Tamaki Drive west of Ngapipi Road for a typical week is summarised in Appendix B. The
table shows the flows are very tidal in the AM and PM peak periods. In the morning peak period Tamaki Drive
typically carries eastbound flows of 500 vehicles per hour and westbound flows of around 2,500 vehicles per
hour. In the evening peak period, Tamaki Drive typically carries eastbound flows of 2,200 vehicles per hour and
westbound flows of 1,000 vehicles per hour.
In the interpeak period traffic flows are lower and approximately even in directional split, peaking in the early
afternoon at around 1,000 vehicles per hour in each direction.
7
https://at.govt.nz/cycling-walking/cycling-and-walking-programme/
12
Traffic Assessment Report
In the weekend, peak flows are similar to those in the weekday interpeak period. They peak at around
1,100 vehicles per hour in each direction in the early afternoon.
The high flows in the weekday AM and PM periods suggest that these periods are critical in terms of the design
and operation of the intersection. In the weekend, traffic flows are at all times considerably lower. For this
reason the weekend counts were not modelled and were not considered further in this assessment.
It is anecdotally noted that in weekends there may be more cycling and walking trips through the int ersection
than on weekdays. However, the demands from these modes would not affect the performance of the
intersection to the extent that weekend periods became critical to modelling the proposed intersection’s
performance as cyclist flows are low relative to vehicles.
3.3.2
Turning flows at the Tamaki Drive / Ngapipi Road Intersection
Existing turning flows at the intersection are shown in Table 3-1. The existing intersection average weekday
th
rd
flows are derived from observed turning counts undertaken by Auckland Transport between 17 -23 November
2015 using 15 minute recording periods. These flows show the AM peak hour (7:45-8:45am), the PM peak hour
(5:00-6:00pm) and an interpeak period (derived from lowest flows for each movement between the AM and PM
peaks as an approximation for an interpeak period).
Table 3-1: Existing Intersection Flows (average weekday counts; November 2015)
AM peak hour
Approach
Interpeak hour
(derived)
PM peak hour
Turn
Light
Heavy
Total
Light
Heavy
Total
Light
Heavy
Total
Ngapipi
Road
Left
Right
1,581
2
25
0
1,605
2
442
16
22
1
464
17
442
2
22
0
464
2
Tamaki
Drive (east)
Left
Through
19
1,402
1
15
20
1,417
46
456
0
12
46
468
19
456
0
12
19
468
Tamaki
Drive (west)
Through
Right
293
166
17
17
310
183
1,348
905
15
12
1,363
917
293
166
15
12
308
178
In the AM peak, the table shows there are very high left turn flows from Ngapipi Road into Tamaki Drive
(1,580vph) and westbound through flows along Tamaki Drive (1,400vph). The left turn flow of 1,580vph is
around the capacity for a single traffic lane in an urban area8.
In the PM peak, the flows are very high for the Tamaki Drive west approach. The through movement is around
1,360 vehicles per hour and the right turn movement is around 920 vehicles per hour.
In all periods few vehicles turn right from the Ngapipi approach. This reflects it being almost impossible to safely
find gaps in the opposing Tamaki Drive traffic to turn right. For this reason it is likely that drivers avoid this
movement, particularly during peak periods.
Heavy vehicle flow is low and contributes approximately 2% of the total vehicle traffic using the intersection in
peak hours.
3.4
Existing Road Conditions
3.4.1
SIDRA Model
The existing intersection performance was modelled using a software package SIDRA Intersection 6.1 using
flow data and queue length data from recent surveys to calibrate the model.
8
Based on guidance from Austroads
13
Traffic Assessment Report
Intersection modelling of the existing flows and existing layout was undertaken to serve as a comparison for the
option modelling. To model the existing context, the average weekday counts from Table 3-1 were used,
although the peak 15 minutes within the peak hour (8:00am-8:15am and 5:15pm-5:30pm) were input into
SIDRA where SIDRA then factors these up to hourly flows. The peak 15 minute volumes for the westbound
through movement on Tamaki Drive were increased by 65 vehicles to reflect the increase in queue in this period
(converting throughput to model demand). Low volume flows were estimated using the lower counter peak flows
from the peak periods.
Gap acceptance input parameters were modified to reflect a reverse priority situation observed in the AM peak
th
and so the outputs are consistent with the 95 percentile queue lengths. This is due to site observations that
opposing westbound traffic typically gives way to both the north-bound right turning vehicles and east-bound
approach right turning vehicles. This traffic is moving slowly due to a merge of the T2 lane with the traffic lane
some 150m east of the intersection and this merge and westbound traffic volumes is the basis of the queuing on
the eastern approach, not the reverse priority.
3.4.2
Existing Queues
The average weekly maximum queue lengths on the intersection approaches were calculated using data from a
th
rd
survey undertaken by AT between 17 and 23 November 2015. These maximum queue lengths are shown in
Table 3-2, where it is clear the longest queues form on the Tamaki Drive (east) approach in the AM peaks.
Table 3-2: Existing Maximum Queue Lengths
Average weekly maximum queue lengths (m)
Average weekly 95%ile queue lengths (m)
AM
AM
Approach
Ngapipi Road
Tamaki Drive (westbound)
Tamaki Drive (eastbound)
PM
PM
250
20
90
20
1800
30
1720
20
80
620
60
570
The data shows long queues occur in the AM peak on Tamaki Drive in the westbound direction (average
1,720m). These queues result from the merge in the two westbound traffic lanes at the end of the T2 lane. In
the PM peak, there are long queues on Tamaki Drive in the eastbound direction (average 570m). This is due to
the lack of capacity for the right turn movement.
3.4.3
Results of Intersection Modelling
The existing model outputs are shown in Figure 3-4, displaying the Level of Service (LOS) for each approach
lane. More detailed modelling outputs can be found in the SIDRA Modelling Report. This report has been
appended in Appendix C.
14
Traffic Assessment Report
2015 AM peak Base
2015 PM peak Base
2015 Base low volume
Figure 3-4: Existing intersection models - level of service outputs
The results show the intersection operates with varying LOS due to the highly tidal nature of the peak traffic
patterns, with:

LOS F for the Tamaki Drive eastern approach through movement in the AM peak (accounting for the
merge);

LOS F for the Tamaki Drive western approach right turn in the PM peak and Ngapipi right turning
movements;

Free flowing in the low volume hours with the lowest LOS D for the Ngapipi right turning movements.
3.4.4
Route Security and Trip Reliability
Areas along the Orakei coastline that are known to be affected by coastal inundation include Tamaki Drive. 9
Impacts of inundation “may include damage to property and infrastructure, effects on business, danger to
people and closures of k ey transport routes. The seawalls along Tamak i Drive have been overtopped and
flooded numerous times during storm events, causing traffic and access issues.”
3.4.5
Road Conditions on Alternative Routes
Tamaki Drive is the main transport route connecting the city to the eastern suburbs. Past closures have been
due to major traffic accidents as well as storm events (causing inundation) and have caused large traffic delays
9
and congestion. An alternative route to avoid the intersection would involve a detour of up to 10km to travel via
Patteson Avenue, Kepa Road, Orakei Road, Shore Road, Ayr Street and Parnell Road (Route 1 in the below
diagram).
9
Orakei Local Board Hazard Report, by Civil Defence and Auckland Council. Undated. Retrieved online May
2016.http://www.aucklandcouncil .govt.nz/en/environmentwaste/naturalhazardsemergencies/hazards/pages/localboardshazardreports.aspx
15
Traffic Assessment Report
Tamaki
Ngapipi
intersection
Auckland
CBD
Route 1
Route 2
Route 3
Figure 3-5: Alternative Routes
Alternative route 1 is through busy, often congested, urban and residential streets and is likely to be only used
in emergency conditions or if the intersection was closed altogether. In this sense, no efficient alternative route
exists for everyday traffic. Other even longer routes (Routes 2 and 3) could also be used in exceptional
circumstances.
3.4.6
Side Roads
There are no side roads within 700m of the intersection, so side roads are not expected to be affected by the
intersection performance. The exception is queuing on the Tamaki Drive eastern approach in the AM peaks,
during which maximum queues have been recorded as 1.8km in length; extending beyond Kelly Tarltons and
across residential streets: Okahu Street, Watene Crescent and Kitemoana Street.
3.4.7
Geometry and Operation
The existing intersection geometry is constrained by the seawalls on two sides, the Paritai South Reserve and
the existing Ngapipi Estuary Bridge. These restrictions essentially dictate the layout of the intersection.
The bridge itself has substandard lane widths (being approximately 3m wide). The bridge also has vertical crest
curve which limits approach visibility of the intersection.
The SAR also identified the following operational issues at the intersection:

The absence of pedestrian crossing facilities;

Limited visibility from Ngapipi Road looking east onto Tamaki Drive (due to vegetation and cliff face, posing
associated capacity constraints);

The left turn slip lane from Ngapipi Road posing a hazard for cyclists (as the cycle lane ends before the slip
lane and cyclists must stop and give way whilst between two live lanes);

The gap selection of vehicles turning right from Tamaki Drive into Ngapipi Road.
3.5
Crash Performance
Safety, as has been noted previously, is the key driver for the Project, and the extent of the safety issues was
highlighted within a list of the Top 100 High Risk Intersections which was produced by NZTA based on crash
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Traffic Assessment Report
data collected from the CAS crash database over the 10 year period between 2003 and 2012 10. The intersection
th
was ranked 10 within the list.
The reported crash history for the intersection has been updated for the five year period January 2011 –
December 2015. This data has been included within Appendix D and has been used as inputs in the crash by
crash analysis consistent with procedures set out in the Economic Evaluation Manual11 (EEM).
Twenty-one crashes occurred within 50m of the Tamaki Drive / Ngapipi Road intersection in the past five years.
Of these, sixteen (76%) crashes occurred at the intersection and a further five to the south, east or west of the
intersection on Ngapipi Road or Tamaki Drive. A crash diagram showing the crashes is in Figure 3-6.
10
11
NZ Transport Agency, High Risk Intersection. Retrieved online May 2016. https://www.nzta.govt.nz/assets/resources/high-risk-intersectionsguide/docs/high-risk-intersections.pdf
NZ Transport Agency, Economics Evaluation Manual, https://www.nzta.govt.nz/resources/economic-evaluation-manual
17
Traffic Assessment Report
Figure 3-6: Crash Diagram
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Traffic Assessment Report
An overview of the data is shown in Table 3-3. There were no fatal or pedestrian crashes in this five year period.
Table 3-3: Crash overview by year and crash severity
Year
Fatal
Serious
Minor
Non-injury
Annual Total
2011
0
2
1
0
3
2012
0
0
4
2
6
2013
0
0
1
1
2
2014
0
1
2
4
7
2015
0
0
2
1
3
Total
0
3
10
8
21
Of the total 21 crashes:
1)
2)
3)
4)
5)
Nine (43%) involved cyclists and three (14%) involved motorcyclists

All motorcyclists accidents were attributed to the motorcyclist rather than other parties;

All bar one of nine cyclists’ crashes was attributed to vehicle drivers failing to give way when turning
right into Ngapipi Road to oncoming through traffic; the remainder was attributed to cyclist colliding
with another cyclist upon entering the shared path on the northern side of Tamaki Drive.
Three (14%) were serious injury crashes, of which:

Two (10%) involved cyclists; both attributed to vehicle drivers failing to give way when turning right into
Ngapipi Road to oncoming through traffic;

One (4%) involved a motorcyclist (incorrectly using the cycle lane; hit by turning bus).
Ten (48%) were minor injury crashes, of which:

Six (29%) of which involved cyclists; all bar one were attributed to vehicle drivers failing to give way
when turning right into Ngapipi Road to oncoming through traffic ;

Two (10%) involved motorcyclists (too fast and loss of control on slippery surface);

Two (10%) involved vehicles changing lanes and overtaking vehicle hit vehicle turning right ;
Of the eight (38%) non-injury crashes, four involved right turning movements:

Three (14%) involved vehicles turning right out of Ngapipi Road failing to give way; one hit a cyclist;

One (4%) involved a vehicle turning right from Tamaki Drive into Ngapipi Road; hit another vehicle.
Of the 13 (62%) injury crashes, 39% were attributed to poor observation and 28% to a failure to give way or
stop.
Cyclists are significantly overrepresented in the crashes. In particular there is a clear pattern of crashes relating
to eastbound drivers turning from Tamaki Drive to Ngapipi Road and failing to give way to westbound cyclists.
The total of 11 crashes due to right turning movements (eight from Tamaki Drive; three from Ngapipi Road) are
shown in Figure 3-7 by the modes hit.
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Traffic Assessment Report
Figure 3-7: Modes hit by right turning vehicles which failed to give way ( total of 11 right turn crashes)
For the eight crashes involving the right turn from Tamaki Drive into Ngapipi Road, seven (88%) hit a cyclist and
only one (12%) another vehicle.
3.6
Parking Provision
Generally there is little car parking provision in the vicinity of the intersection. There is free unrestricted on street
parallel parking available on the northern side of the Tamaki Drive eastern approach which starts 100m from the
intersection. There is 120m (approximately 17 spaces) of free unrestricted on street parallel parking car parking
outside the boatsheds 120m from the intersection along Ngapipi Road. Anecdotally, car parking nearby is used
informally for ‘park and ride’ for commuters who switch modes to use public transport services to reach the
central city.
Issues relating to car parking were not identified in the SAR. Auckland Transport undertook a parking survey in
2013 and found that there was generally sufficient parking along Tamaki Drive in the location of the Project.
3.7
Walking and Cycling
3.7.1
Pedestrian and Cyclist Facilities
The cycle and pedestrian facilities have generally been designed and fitted within the available space at the
intersection. A summary of existing facilities is provided in Figure 3-8.
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Traffic Assessment Report
Cyclists
approaching
warning sign;
facing west
Shared
path
On road
cycle lane
Footpath
Figure 3-8: Pedestrian and cyclist facilities
Footpaths are provided along each side of the carriageway for all the intersection approaches. These vary in
width and lateral clearance but appear to be typically 1.5m in width (current standards require 1.8m width). The
footpath along the southeast corner of the intersection connects the westbound bus stop on Tamaki Drive (160
metres east of Ngapipi Road) and the southbound bus stop on Ngapipi Road. Marked pedestrian and cyclist
paths, with a combined width of 1.5m, are provided along both sides of the Ngapipi Estuary Bridge. The marked
paths on the northern side of Tamaki Drive continue along the northern side of Tamaki Drive east and west of
the intersection.
Tamaki Drive has a westbound cycle lane extending through the intersection. A marked cycle lane begins on
the Tamaki Drive east approach around 80m east of the intersection, and ends at the left turn slip lane from
Ngapipi Road, requiring cyclists to stop and give way to slip lane traffic in order to reach a ramp onto the
westbound shared use path.
This is a standard design solution for left turn slip lanes, however in this instance there are a number of issues
resulting from this layout. Firstly most commuter cyclists do not stop and cross onto the separated paths.
Instead they continue westward along the left side of the through traffic lane and then weave across to the left
side of the left turning lane. Secondly left turn flows are high, so in the morning peak period there is a delay for
cyclists crossing the slip lane. Thirdly the pram crossing can only be negotiated at slow speed and the
separated path on the south side of the bridge is then very narrow. Anecdotally confident commuter cyclists are
known to choose to stay on the carriageway along Tamaki Drive and over the bridge to avoid having to navigate
past pedestrians on the shared use path.
In 2010 a “cyclist approaching when flashing” variable message sign was installed to warn vehicles turning right
into Ngapipi Road that cyclists were approaching the intersection from the east. This is shown in Figure 3-9.
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Traffic Assessment Report
Figure 3-9: Cyclist approaching variable message warning sign (Installed in 2010)
This warning sign was intended to be a short term measure prior to intersection upgrade, but the 2011-15 crash
history shows a continuing problem from these crashes still occurring. Further, the cycle detector loop which is
located 70 metres east of the intersection on Tamaki Drive cannot detect carbon fibre bikes.
Currently, there is no provision for pedestrian crossings at the intersection, with only an uncontrolled refuge
island on Tamaki Drive 60m east of Ngapipi Road.
3.7.2
Demand
Tamaki Drive is known to be a popular walking and cycling route for commuters and leisure trips. The SAR
reports that pedestrian demand was observed to be primarily along Tamak i Drive and mostly on the north side.
A minor crossing demand was observed at or near the intersection, even at the refuge island.
th
The cycle demand was recorded as average weekday flows from observed turn counts taken between 17 and
rd
23 November 2015 using 15 minute recording periods.
Table 3-4: Existing cycle counts (cycles per hour)
Approach
Turn
AM peak hour
PM peak hour
Ngapipi Road
Left
Right
11
0
3
0
Tamaki Drive (east)
Left
Through
1
30
7
9
Tamaki Drive (west)
Through
Right
8
1
25
7
This data suggests around 50 cyclists travel along Tamaki Drive west of the intersection in each peak hour. In
the AM peak, around 40 cyclists travel towards the CBD and around 10 in the opposite direction. In the evening
peak around 30 travel towards the eastern suburbs and 10 towards the CBD. Cycle demand through the
intersection is similar in pattern to the pedestrian movements, with most cycle demand being along Tamaki
Drive and a lesser proportion from Ngapipi Road.
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Traffic Assessment Report
3.8
Public Transport Network
There are four bus stops located in the immediate vicinity of the intersection. They are:

Tamaki Drive: eastbound stop is 40m east of Ngapipi Road; westbound stop is 160m east of Ngapipi Road

Ngapipi Road: southbound bus stop on Ngapipi Road 40m south of Tamaki Drive; northbound stop is 70m
south of Tamaki Drive
There are numerous existing bus services that use the intersection to travel along Tamaki Drive (745, 750, 755,
756, 757, 767, 768, 769, 551X, 553X, 554X) and to travel between Tamaki Drive (west) and Ngapipi Road (710,
713, 715, 716, 717, 685X). Aside from some express services, these services use the bus stops along Tamaki
Drive and Ngapipi Road.
The demand at the bus stops has not been quantified but the stops themselves are anecdotally considered to
be infrequently used. There are almost no residential or commercial properties nearby and these bus stops are
considered to be used mostly by commuters who have parked nearby. On occasions they are also used by
residents who use a path that runs down from Paritai Drive to the intersection.
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Traffic Assessment Report
4. The Proposed Design
The broad features of the proposed design are shown in Figure 4-1.
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Traffic Assessment Report
Signalised with pedestrian
crossings on all three approaches
Extended seawall
and reclamation
Two approach
lanes
Approximate extent
of reclamation
Cycle lanes and advance stop
boxes
Figure 4-1: Proposed design
25
Traffic Assessment Report
Drawings for the proposed design can be found in Appendix A of the AEE Report. Important features of the
layout include:

Dual left turn lanes for the Ngapipi Road approach;

Dual through lanes for the Tamaki Drive (west) approach;

Crossing facilities for pedestrians on all approaches;

A reclamation on Tamaki Drive which allows for the reconfigured intersection and cycling/pedestrian
facilities;

Cycle facilities including cycle lanes, advanced stop boxes and separated paths; and

A separated path on the Ngapipi approach to the intersection which is located within a reclamation on the
seaward side of existing pohutukawa trees.
The reclamation on the northern side of Tamaki Drive, which has been described above, is required to
accommodate the current project. Use of the reclamation can potentially be rearranged in the future to provide
for changes to the Ngapipi Bridge which will be investigated by AT. These potential future works do not form
part of this project.
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Traffic Assessment Report
5. Project Shaping
The proposed layout which has been developed as the detailed design is very similar to the design which was
investigated in the Scheme Assessment stage of the Project. This preferred scheme assessment layout is
shown in Appendix A.
In developing the proposed design, care has been taken to minimise any impact on the existing environment
and trees. Safety has also been a key factor in shaping the design. These refinements are:

The design has been refined to provide for the shared path on the seaward side of the five pohutukawa
on the western side of Ngapipi Road.

The dual left turn lanes for the Ngapipi approach were realigned slightly to improve their alignment for
turning vehicles.

A splitter island was added between the Ngapipi approach right turn lane and the Ngapipi southbound
lane to improve safety.

Along Tamaki Drive the traffic lanes were realigned slightly to improve the alignment of the eastbound
traffic lane.

The width of the carriageway has been minimised by the use of narrow 3.2m wide through traffic lanes
and 3.0m wide turning lanes, and also through careful design for heavy vehicle tracking.
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Traffic Assessment Report
6. Assessment of Effects
6.1
Modelling of the Detailed Design Layout
The proposed design was modelled in SIDRA to compare this design with the existing layout. The outputs of
this analysis were used to determine travel time differences (due to intersection delay differences).
The phasing used in the SIDRA modelling is shown in the below diagram.
Note: Phase D w as only included in sensitivity testing as few pedestrians are expected to cross the eastern approach
Figure 6-1: Signal phasing
In the proposed design models, where pedestrian crossing stages were included a nominal 200 pedestrians per
hour was input as the demand for each crossing. Pedestrian crossings of Ngapipi Road in Phase A and Tamaki
Drive (west) in Phase C were included in the option models.
As a sensitivity test, a further phasing option was tested for an additional Phase D including a pedestrian
crossing on Tamaki Drive (east) which increases the optimised cycle time.
The interpeak was modelled to determine the effects of the project at times of the day when flows are moderate.
6.2
Forecast Flows used for Modelling
No changes to input flows were made to model the detailed design layout, aside from sensitivity testing (e.g.
testing of future growth scenarios and scenarios related to use of pedestrian crossing facilities).
The detailed design layout may cause slight changes to the wider network traffic patterns, with rerouting to or
away from the intersection. These changes are difficult to forecast even with network wide modelling,
particularly with any meaningful accuracy for a single intersection, and hence no network wide modelling was
undertaken.
6.3
Modelled Intersection Performance
The results of the SIDRA modelling are shown in Table 6-1, Table 6-2, and Figure 6-2.
28
Traffic Assessment Report
Table 6-1: Average intersection delay outputs from intersection modelling
Model
Delay (seconds)
AM peak hour
PM peak hour
100
60
3
Signalisation (excluding Phase D )
134
26
17
Signalisation (including Phase D)
213
62
-
Existing
12
Interpeak
Table 6-2: Intersection approach 95%ile queue lengths outputs from intersection modelling (excluding Phase D)
Modelled 95%ile queue lengths (m)
Approach
AM peak hour
PM peak hour
Ngapipi Road
Tamaki Drive (east)
290
610
40
140
Tamaki Drive (west)
90
520
Interpeak
20
50
40
Key: ModerateIncrease; Increase; No change; Decrease
2015 AM peak Option (inc. D)
2015 AM peak Option (exc. D)
2015 PM peak Option (inc. D)
2015 PM peak Option (exc. D)
2015 Interpeak
Figure 6-2: Signalised intersection models - level of service outputs
12
Phase D includes operation of the eastern approach cross walk
29
Traffic Assessment Report
Modelling indicates that the proposed design is expected to overall impose slightly greater travel times. Delays
will increase in the AM peak and interpeak and decrease in the PM peak. It has a moderating effect on queue
lengths. Signalisation with optimal cycle time will reduce the longest 95%ile queue lengths for each peak, while
the other 95%ile queue lengths increase but stay below 300m.
The key changes are outlined in Table 6-1, Table 6-2 and Figure 6-2, and are explained below:

In the AM peak, increased delay is due to the delay imposed on the Ngapipi Road left turn and right turn
(currently experiencing reverse priority) movements. Tamaki Road east through movements experience
little appreciable change, as the existing reverse priority and lane merge are no longer required, but are
offset by reduced priority through signalisation. The 1720m 95%ile queue on Tamaki Road east reduces to
610m.

In the PM peak, reduced delay is due to significant reduction in delays for Tamaki Drive west approach
right turning traffic to Ngapipi Road. The 570m 95%ile queue on Tamaki Drive west reduces to 520m.

In the low volume periods, signalisation adds only minor delays on all approaches except the right turn into
Ngapipi Road, which experiences significant delay. The effect of this is that the average delay for the
intersection increases from 3 seconds to 17 seconds.
The results for modelling with phase D included show that if high use was made of the cross walk Tamaki Drive
(east) approach cross walk in the peak periods, then the performance of the intersection would greatly reduce.
The 95%ile queue lengths indicated by modelling suggest that AM peak queuing along Tamaki Drive is reduced
and will only extend eastwards 610m, only affecting the Royal Akarana Yacht Club access. No other
approaches are expected to have 95%ile queue lengths that reach any other accesses or side roads.
6.4
Crash Performance
It can be reasonably expected pedestrian and cyclist safety will be improved from the space and facilities
dedicated to these modes. These are the most vulnerable road users and reducing these crashes will likely
have a positive impact on future crash severity (as a high proportion of crashes involving vulnerable road users
result in injury), as well as improve the amenity and efficiency for pedestrian and cyclists . The marked cycle
lanes and advance stop boxes also serve to remind drivers of the presence of cyclists and make for more
predictable interactions between cyclists and vehicles.
Many of the existing crashes relate to right turn movements (52%) and the signals will provide protected right
turning phases (i.e. right turn arrows) that can be expected to improve safety for these movements by
separating them in time. Further, the addition of dedicated lanes for turning traffic at Tamaki Drive east
approach and Ngapipi Road (as left turning lanes) may potentially reduce vehicle crashes; this potential
reduction is estimated to be in the range of 20-45%. 13
However signalisation of the intersection may introduce other crash trends (such as failure to observe red signal
or too fast on approach). A comparison of the intersection types for urban T-intersections shows that the fatal
and serious crash rate is similar for all control types (i.e. roundabouts, traffic signals and priority control).14
6.5
Walking and Cycling
The proposed upgrade of the intersection will greatly improve facilities for walking and cycling, by adding
marked cycle lanes, cycle ramps, separated paths, advanced stop boxes, pedestrian crossing facilities and
refuges in the median islands. These facilities are expected to increase safety, amenity , access and efficiency
for active modes, and support mode shift objectives. This is a major benefit of the Project.
13
14
KiwiRap, Potential Reductions (%) in Various Injury Crash Types. Retrieved online May 2016. http://www.kiwirap.org.nz/road_safer.html
NZ Transport Agency, Draft for consultation: High Risk intersection Guide, Figure 6-3. Retrieved online May 2016.
http://www.nzta.govt.nz/assets/consultation/high -risk-intersections-guide/docs/high-risk-intersections-guide.pdf
30
Traffic Assessment Report
These facilities will also integrate with cycle improvements within the wider network. Auckland Transport’s
proposed cycle network shows plans for a cycleway along Ngapipi Road, Kepa Road and connecting with
another proposed cycleway along Kohimarama Road beyond 2018.15
The Urban Cycleway Glen Innes to Tamaki Drive Shared Path is expected to be completed 2017/18, and will
provide an off road cycleway and walking connection from the Eastern Suburbs (St Johns, Meadowbank and
Glen Innes) to the Central City, and bypasses the Tamaki / Ngapipi intersection. However cyclists from Mission
Bay and Orakei suburbs are still likely to use Tamaki Drive and go through the intersection.
6.6
Geometry
The proposed design will generally provide a high standard of geometry, almost entirely meeting design
recommendations within Austroads and Auckland Transport guidelines.
Some slight departures have been required due to existing constraints (pohutukawa trees within the Paritai
South Reserve and in the road reserve, the estuary and harbour adjacent to the intersection and the Ngapipi
Estuary Bridge) however none of these are expected to significantly affect the performance and safety of the
intersection. These include:

The Tamaki Drive west approach stopping sight distance is only 40m, effectively applying a design speed
of 40km/h (not 60km/h). This is essentially an existing issue due to the bridge alignment;

View of traffic signals for the Ngapipi Road approach dual left turn lanes is partially obscured by the
pohutukawa trees on the seaward side of the approach. It is not expected that this will be a safety issue
however as the low speed geometry of this movement will ensure vehicles are driving slowly when
approaching the traffic signals.

The vertical clearance to limbs from the large pohutukawa tree on the south-eastern corner of the
intersection (identified as tree 18 in the Arboricultural Assessment attached to the AEE) is limited. Bark
damage to the trees lateral branches shows that the tree has been repeatedly struck by high-sided
vehicles. In order to reduce the potential for vehicles to strike the tree, the kerb has been moved 2m
further from the tree.

The separated paths do not fully meet the aspirational Tamaki Drive Master Plan:
-
Adjacent to the eastbound bus stop on Tamaki Drive it is not possible to provide a 6m wide path
without encroaching into reclaimed land set aside for future widening of Tamaki Drive and the Ngapipi
Estuary Bridge; a 4m wide shared path is provided instead (1.5m footpath and 2.5m cycle lane);
-
On Ngapipi Road, it is not possible to provide a 4.5m wide path without additional reclamation. A 4.3m
wide shared path is provided instead and also a 1.5m on road cycle path on the approach to the
intersection;
-
The separated paths are not split level between walking and cycling.
Further, in developing the vertical alignment, the pavement level has been raised to reduce the severity of an
existing the sag curve at the intersection. The centreline will be raised by approximately 200mm , however this
will provide only a marginal improvement for sight distance to the intersection for vehicles coming over the
vertical crest curve on the bridge.
Advanced warning signs and a high outreach signal arm further enhance visibility of the intersection for
eastbound traffic.
6.7
Route Security and Trip Reliability
While signalisation overall increases travel times through the intersection, it will provide more reliable travel
times under congested conditions, particularly for minor movements. It is possible that this improved reliability
may attract traffic from other routes (for example those shown previously in Figure 3-5 on page 16). Overall
amount of rerouting is likely to be small as changes in capacity and travel time are comparatively minor.
15
Auckland Transport, Proposed Auckland Cycle Network. Retrieved online. https://at.govt.nz/media/1152675/Proposed -Auckland-Cycle-Network.pdf
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Traffic Assessment Report
6.8
Provision for Over-Dimension Vehicles
The proposed design allows for the existing over-dimension vehicle route along Tamaki Drive west of Ngapipi
Road. The required vertical and lateral clearances (6m by 10m respectively) are met on the basis that the overdimension vehicle route will use the dual left turn lanes on Ngapipi Road. The southbound traffic lane on
Ngapipi Road is unlikely to provide adequate vertical (to overhanging trees) or horizontal clearances (between
kerbs), so over-dimension vehicles are likely to need to travel contra-flow with Pilot Vehicles via the dual left turn
lanes.
6.9
Parking
There is only a minimal impact on car parking. The greatest impact is the permanent removal of 90m of parallel
on street parking on the northern side of Tamaki Drive east of the intersection (approximately 13 spaces). The
effect of this is seen to be minimal as this parking does not serve nearby development, and essentially is mostly
used as park and ride parking.
Parking along the western side of Ngapipi Road outside the boatsheds is not affected.
6.10
Travel Demand Management
Travel demand management has not been explicitly included in the design solution for the intersection, however
the safety improvements for cyclists, and improvements in access and movement for pedestrians and cyclists
supports the overall objectives of travel demand management by encouraging use of active modes and public
transport.
6.11
Emergency Vehicle Access
Signalisation also allows better access by emergency vehicles and alternative configuration under temporary
traffic management, due to the increased number of lanes and intersection footprint, which better allow for
overtaking by emergency vehicles. The design also allows potential future proofing for a second Tamaki Drive
eastbound through lane, which will allow greater capacity and improved route security in future.
No clearance issues are expected with large vehicle movements through the intersection, aside from the left
turn into Ngapipi Road where there is evidence of bark damage indicating vehicle strike to overhanging tree
branches. As discussed in section 6.6 in order to reduce the potential for vehicles to strike the tree (tree 18), the
kerb has been moved 2m further from the tree. This clearance may pose constraints for high vehicles but will
accommodate fire appliances 16. A permanent warning sign for the 4m vertical clearance is included in the
design.
6.12
Public Transport
There is not expected to be more than a minor impact on the existing bus servi ces, except perhaps for the
removal of approximately 13 parks which are essentially used for park and ride. Drivers using these carparks
would likely seek parking close to another bus stop. Access to the bus stops will be enhanced by improved
facilities for pedestrians to cross Tamaki Drive and Ngapipi Road to reach the bus stops .
6.13
Construction Effects
Construction is expected to extend to approximately one year in duration, due to the highly constrained site and
the need to maintain existing traffic volumes through the intersection. The works will be of fairly low intensity to
minimise the potential impacts on existing traffic flows .
16
New Zealand Fire Service, Emergency vehicle access guidelines. Retrieved online May 2016. http://www.fire.org.nz/business-fire-safety/buildingdesign/Documents/Emergency%20vehicle%20access%20guidelines.pdf
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Traffic Assessment Report
The construction staging plans (refer to Construction Staging sketches ZB01489-ECC-SK-0040 to 0043 in
Appendix E) provide that the works will be undertaken in four main stages (indicative only):

Stage 1- Reclamation along north side of Tamaki Drive (east to west), with Tamaki Drive traffic lanes
narrowed and pushed towards the south;

Stage 2 - Reclamation on the west side of Ngapipi Road (north to south), with Ngapipi Road traffic lanes
narrowed and pushed towards the east;

Stage 3 - Traffic diverted onto the new reclamation along Tamaki Drive and the carriageway narrowed on
Ngapipi Road, to undertake works on southeast corner;

Stage 4 - Traffic diverted back onto carriageway while works are completed within the Tamaki Drive
reclamation.
This staging is indicative only.
Generally all existing traffic lanes and turning movements will be maintained during construction to ensure there
is minimal impact on traffic movement. Even with the existing lanes and movements being maintai ned, there will
still be slight increases in delays due to narrowing of the carriageway, reduced visibility, turning movements into
or out of the site, loose stone or uneven surfaces and a reduced standard of the geometry.
At times to undertake works it may be necessary to temporarily close a traffic lane. These closures will be timed
to ensure the impact on traffic movement is minimised.
The separated paths, cycleways and footpaths may require temporary narrowing and a short section of the
eastern footpath on Ngapipi Road will be closed during Stage 3 (refer to sketch ZB01489-ECC-SK-0042).
Bus stops will be temporarily relocated during construction. Signs will be provided to direct bus patrons to their
temporary location. Note that no practical detours are available for bus services (or other traffic) so these
services are expected to be continued through the site during construction.
The existing T2 transit lane on Tamaki Drive east approach will remain operational during construction and T2
users and buses will still be required to merge with the general traffic lane as they do currently. The main impact
to bus services is likely to be some delay due to traffic management when travelling through the works.
Traffic flows from construction traffic are typically expected to be low, in part due to the long construction period.
For this reason, the additional traffic flow from construction traffic is unlikely to be perceptible amongst the
background flow already using the surrounding road network.
Some existing car parking or road reserve space may be closed for construction vehicles and plant, and for
temporary traffic management. The reduction in parking during construction works is expected to be the same
as the 90m of on street parallel parking permanently removed on Tamaki Drive.
The nearest property accesses are the Orakei Marina and Royal Akarana Yacht Club some 450m east along
Tamaki Drive and a residential property access starting 520m south along Ngapipi Road. There may be a slight
effect from queue length increases during the construction period and so potentially they may block back past
property accesses and side roads more frequently than they do currently.
The speed limit will be reduced through the site to 30km/h at all times during construction. This reduction in
speed will be necessary due to the reduced level of visibility and standard of geometry provided. This reduced
speed will also better allow for cycle movement, particularly where on road cyclists are forced to share traffic
lanes with traffic.
A traffic management plan (TMP) will be required as a condition of consent and will detail how traffic and
construction will be managed to minimise impacts. The TMP may also describe the maximum level of delay
which is acceptable when closures occur and the mitigation measures which would be implemented.
The TMP will also address issues such as:
33
Traffic Assessment Report

Impact on vulnerable road users including pedestrians and cyclists;

On-site traffic monitoring;

Measures to improve road safety on site;

Emergency response and incident management; and

Temporary Traffic Management Measures.
34
Traffic Assessment Report
7. Measures to Avoid, Remedy or Mitigate Effects
A number of measures that have been incorporated into the design to avoid, remedy or mitigate the potential
adverse effects of the Project in terms of traffic.
Features that have been incorporated to minimise the traffic effects include:
-
Construction of a second left turn lane for the Ngapipi approach to ensure the capacity for the left turn
movement is essentially retained;
-
Provision of a flashing yellow warning light on the Ngapipi Road approach to ensure drivers are aware
when the traffic signals are red for the left turn movement at the intersection and they need to stop.
-
Extending the T2 lane on Tamaki Drive as far as the intersection to reduce the effects from the merge
of the T2 lane;
-
Temporary traffic management measures will be included in the Construction Management Plan to
avoid or minimise effects on traffic flows during the construction period.
8. Conclusions and Recommendations
Overall, the Project is expected to greatly enhance amenity and safety for pedestrians and cyclists. While travel
times for motorists may at times be slightly longer, the Project promotes a shift to active modes, and has a
minimal impact on traffic.
35
Traffic Assessment Report
Appendix A. Scheme Assessment Layout – Preferred Option 1
36
Traffic Assessment Report
37
Traffic Assessment Report
Appendix B. Traffic flows on Tamaki Drive between Solent Street
and the Ngapipi Estuary Bridge
38
Traffic Assessment Report
Data was supplied by AT for a survey conducted on Tamaki Drive between Solent Street and the Bridge. Count start date was Wednesday 11 November 2015
Eastbound - Both Lanes
Evening
Middle Day
Morning
Wed
Thu
Fri
Sat
Sun
Daily Maximums
Mon
Tue
Dir1/Lane1 Dir1/Lane2 Dir1/Both
Westbound - Both Lanes
All Lanes
Daily Maximums
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Dir2/Lane1 Dir2/Lane2 Dir2/Both All Lanes
0515
0615
112
93
93
90
72
75
102
58
60
112
313
274
314
133
113
274
272
425
367
407
223
185
349
374
136
188
314
425
0530
0630
178
159
153
108
74
128
163
96
93
178
436
355
441
167
113
372
382
614
514
594
275
187
500
545
176
267
441
614
0545
0645
276
259
269
147
82
213
280
153
147
280
574
509
612
216
147
510
555
850
768
881
363
229
723
835
227
385
612
881
0600
0700
402
412
411
186
92
325
402
221
201
412
801
773
823
257
167
764
826
1203
1185
1234
443
259
1089
1228
318
557
826
1234
0615
0715
514
526
522
235
111
374
509
294
246
526
1160
1123
1194
301
190
1090
1228
1674
1649
1716
536
301
1464
1737
442
842
1228
1737
0630
0730
595
592
587
269
129
453
564
342
258
595
1539
1619
1601
344
224
1534
1694
2134
2211
2188
613
353
1987
2258
612
1119
1694
2258
0645
0745
618
619
583
294
159
466
577
369
257
619
2054
2102
2028
383
261
2006
2158
2672
2721
2611
677
420
2472
2735
838
1369
2158
2735
0700
0800
596
589
564
345
166
466
540
363
239
596
2493
2535
2457
459
281
2416
2598
3089
3124
3021
804
447
2882
3138
1024
1574
2598
3138
0715
0815
559
573
570
423
171
484
492
354
230
573
2777
2825
2703
551
340
2740
2869
3336
3398
3273
974
511
3224
3361
1210
1664
2869
3398
0730
0830
545
558
555
464
173
459
490
332
234
558
2984
2949
2866
660
383
2725
3052
3529
3507
3421
1124
556
3184
3542
1369
1683
3052
3542
0745
0845
540
522
537
505
196
452
486
336
224
540
2961
2976
2794
767
416
2659
3086
3501
3498
3331
1272
612
3111
3572
1426
1660
3086
3572
0800
0900
530
509
544
518
243
432
494
336
218
544
2727
2741
2573
836
482
2599
2911
3257
3250
3117
1354
725
3031
3405
1357
1554
2911
3405
0815
0915
540
519
532
522
282
444
503
332
226
540
2414
2494
2288
858
519
2488
2578
2954
3013
2820
1380
801
2932
3081
1209
1407
2578
3081
0830
0930
528
561
546
566
322
454
550
339
234
566
2057
2110
1941
871
578
2315
2188
2585
2671
2487
1437
900
2769
2738
1109
1228
2315
2769
0845
0945
556
606
591
596
359
485
589
355
256
606
1680
1723
1673
945
622
2002
1750
2236
2329
2264
1541
981
2487
2339
936
1066
2002
2487
0900
1000
586
635
627
653
409
510
621
381
272
653
1433
1501
1435
1048
692
1570
1403
2019
2136
2062
1701
1101
2080
2024
680
891
1570
2136
0915
1015
610
633
641
705
500
526
652
411
294
705
1232
1223
1274
1133
766
1146
1202
1842
1856
1915
1838
1266
1672
1854
531
783
1274
1915
0930
1030
628
628
671
770
598
518
633
452
318
770
1086
1124
1101
1227
831
975
1034
1714
1752
1772
1997
1429
1493
1667
481
793
1227
1997
0945
1045
610
660
696
838
674
548
614
500
338
838
968
1005
1006
1237
874
914
1005
1578
1665
1702
2075
1548
1462
1619
440
812
1237
2075
1000
1100
619
655
711
911
748
557
617
550
361
911
890
907
964
1209
926
876
1008
1509
1562
1675
2120
1674
1433
1625
442
807
1209
2120
1015
1115
658
660
733
951
776
569
629
576
375
951
858
890
917
1182
949
848
1008
1516
1550
1650
2133
1725
1417
1637
440
789
1182
2133
1030
1130
677
667
780
984
784
606
627
602
382
984
801
820
926
1217
988
827
1012
1478
1487
1706
2201
1772
1433
1639
420
806
1217
2201
1045
1145
689
651
815
1011
827
587
643
610
401
1011
826
831
950
1210
999
780
952
1515
1482
1765
2221
1826
1367
1595
423
787
1210
2221
1100
1200
689
665
814
1026
844
598
636
614
412
1026
848
834
989
1216
981
767
927
1537
1499
1803
2242
1825
1365
1563
430
786
1216
2242
1115
1215
684
713
858
1077
898
620
633
638
439
1077
866
852
1019
1265
991
759
925
1550
1565
1877
2342
1889
1379
1558
449
816
1265
2342
1130
1230
687
707
857
1093
918
631
652
649
444
1093
897
920
1073
1228
985
770
884
1584
1627
1930
2321
1903
1401
1536
432
796
1228
2321
1145
1245
705
729
862
1151
932
651
660
683
468
1151
872
918
1051
1214
1006
757
851
1577
1647
1913
2365
1938
1408
1511
414
800
1214
2365
1200
1300
723
770
870
1179
937
656
691
697
482
1179
910
907
1047
1202
1000
769
837
1633
1677
1917
2381
1937
1425
1528
428
774
1202
2381
1215
1315
735
762
885
1162
903
639
716
688
474
1162
909
870
1018
1205
977
779
802
1644
1632
1903
2367
1880
1418
1518
435
770
1205
2367
1230
1330
752
786
932
1153
925
638
736
701
452
1153
909
861
988
1206
950
773
793
1661
1647
1920
2359
1875
1411
1529
442
764
1206
2359
1245
1345
759
809
980
1121
913
638
757
687
434
1121
927
853
1017
1183
957
809
820
1686
1662
1997
2304
1870
1447
1577
436
747
1183
2304
1300
1400
755
808
1013
1112
909
659
751
698
433
1112
884
932
1017
1199
950
797
780
1639
1740
2030
2311
1859
1456
1531
440
759
1199
2311
1315
1415
752
844
1030
1080
956
654
758
685
432
1080
877
956
1050
1191
966
804
813
1629
1800
2080
2271
1922
1458
1571
430
761
1191
2271
1330
1430
801
894
1053
1123
975
699
791
681
442
1123
878
947
1044
1176
998
785
851
1679
1841
2097
2299
1973
1484
1642
418
758
1176
2299
1345
1445
850
924
1063
1129
993
739
820
694
435
1129
881
976
1069
1229
991
777
829
1731
1900
2132
2358
1984
1516
1649
442
787
1229
2358
1400
1500
946
965
1118
1096
1033
786
905
672
461
1118
851
935
1085
1190
999
769
869
1797
1900
2203
2286
2032
1555
1774
418
772
1190
2286
1415
1515
988
968
1172
1142
1037
787
932
704
500
1172
861
947
1135
1155
977
801
867
1849
1915
2307
2297
2014
1588
1799
407
748
1155
2307
1430
1530
1038
985
1227
1087
1072
812
929
703
524
1227
910
972
1207
1120
964
820
858
1948
1957
2434
2207
2036
1632
1787
425
782
1207
2434
1445
1545
1057
1000
1302
1120
1080
849
962
737
565
1302
945
955
1259
1085
949
867
938
2002
1955
2561
2205
2029
1716
1900
451
808
1259
2561
1500
1600
1080
1052
1429
1201
1058
890
992
808
621
1429
1031
997
1305
1096
943
864
990
2111
2049
2734
2297
2001
1754
1982
471
834
1305
2734
1515
1615
1172
1188
1576
1228
1033
1028
1067
894
682
1576
1118
1081
1310
1130
944
879
1048
2290
2269
2886
2358
1977
1907
2115
486
824
1310
2886
1530
1630
1284
1356
1726
1272
985
1204
1251
1004
722
1726
1117
1091
1305
1137
945
919
1107
2401
2447
3031
2409
1930
2123
2358
491
814
1305
3031
1545
1645
1429
1521
1840
1225
987
1351
1421
1122
718
1840
1129
1206
1272
1130
912
898
1110
2558
2727
3112
2355
1899
2249
2531
481
791
1272
3112
1600
1700
1665
1756
1979
1231
978
1562
1579
1259
770
1979
1134
1150
1237
1127
913
888
1078
2799
2906
3216
2358
1891
2450
2657
498
763
1237
3216
1615
1715
1839
1923
2096
1255
991
1841
1821
1371
870
2096
1095
1103
1175
1157
922
871
1015
2934
3026
3271
2412
1913
2712
2836
478
804
1175
3271
1630
1730
2004
2098
2206
1255
995
2037
1987
1430
946
2206
1123
1052
1139
1204
884
806
987
3127
3150
3345
2459
1879
2843
2974
479
835
1204
3345
1645
1745
2203
2270
2295
1307
955
2257
2147
1475
999
2295
1064
962
1081
1210
880
779
926
3267
3232
3376
2517
1835
3036
3073
460
854
1210
3376
1700
1800
2178
2301
2284
1232
944
2330
2135
1462
1047
2330
1004
965
1073
1209
850
772
890
3182
3266
3357
2441
1794
3102
3025
466
825
1209
3357
1715
1815
2216
2271
2196
1145
884
2212
2100
1389
991
2271
961
928
1096
1118
793
716
883
3177
3199
3292
2263
1677
2928
2983
481
749
1118
3292
1730
1830
2071
2124
2004
1122
836
2016
1954
1253
906
2124
907
945
1095
1103
759
703
817
2978
3069
3099
2225
1595
2719
2771
481
734
1103
3099
1745
1845
1810
1887
1781
1064
763
1744
1723
1095
811
1887
898
902
1093
1081
730
662
808
2708
2789
2874
2145
1493
2406
2531
481
715
1093
2874
1800
1900
1623
1632
1539
1010
702
1437
1579
923
740
1632
890
930
1074
1070
676
641
788
2513
2562
2613
2080
1378
2078
2367
456
722
1074
2613
1815
1915
1370
1388
1341
996
656
1213
1353
769
634
1388
836
979
1030
1052
637
596
735
2206
2367
2371
2048
1293
1809
2088
438
702
1052
2371
1830
1930
1193
1161
1213
941
633
1009
1177
703
545
1213
760
976
972
989
575
543
682
1953
2137
2185
1930
1208
1552
1859
399
661
989
2185
1845
1945
1077
980
1116
866
600
828
1042
674
485
1116
712
990
905
933
527
483
618
1789
1970
2021
1799
1127
1311
1660
359
701
990
2021
39
Traffic Assessment Report
Appendix C. SIDRA Modelling Report
40
Traffic Assessment Report
41
Traffic Assessment Report
Appendix D. Results of the CAS Crash Analysis
42
Traffic Assessment Report
43
Traffic Assessment Report
Appendix E. Construction Sequencing
44
Traffic Assessment Report
45