DETAILED DESIGN ROAD SAFETY AUDIT REPORT
SH 1: Waikato Expressway Safety Improvements and
Safer Speeds Classification
Prepared for Safe Road Alliance
September 2016
1982
Act
Information
Official
the
under
Released

1982
Act
Information
Official
the
under
Released

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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
This document has been prepared for the benefit of Safe Road Alliance. No liability is accepted by this
company or any employee or sub-consultant of this company with respect to its use by any other
person.
This disclaimer shall apply notwithstanding that the report may be made available to other persons for
1982
an application for permission or approval to fulfil a legal requirement.
Act
QUALITY STATEMENT
PROJECT MANAGER
AUDIT TEAM LEADER
s 9(2)(a)
s 9(2)(a)
PREPARED BY
s 9(2)(a)

s 9(2)(a)
06/09/2016
Information
REVIEWED BY
s 9(2)(a)

s 9(2)(a)
(Opus)
06/09/2016
s 9(2)(a)
APPROVED FOR ISSUE BY

s 9(2)(a)
07/09/2016
Official
HAMILTON
468 Tristram St, Whitiora, Hamilton 3200
PO Box 13-052, Armagh, Christchurch 8141
the
TEL +64 7 839 0241, FAX +64 7 839 4234
REVISION SCHEDULE
under
Signature or Typed Name (documentation on file).
Rev
Date
Description
No
Checked
Reviewed
Approved
Prepared by
by
by
by
s 9(2)(a)
A
05/09/2016
Draft – For Comment
B
07/09/2016
Final
Released
Status: Final
Project No.: 80508736 Child No.: 0103
August 2016
Our ref: RSA SH 1: Waikato Expressway Safety Improvements and Safer Speeds Classification Draft Report

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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
1
Introduction
1.1
Safety Audit Definition and Purpose
A road safety audit is a term used internationally to describe an independent review of a future road
project to identify any safety concerns that may affect the safety performance. The audit team considers
the safety of all road users and qualitatively reports on road safety issues or opportunities for safety
improvement.
1982
A road safety audit is therefore a formal examination of a road project, or any type of project which
affects road users (including cyclists, pedestrians, mobility impaired etc.), carried out by an independent
competent team who identify and document road safety concerns.
Act
A road safety audit is intended to help deliver a safe road system and is not a review of compliance with
standards.
The primary objective of a road safety audit is to deliver a project that achieves an outcome consistent
with Safer Journeys and the Safe System approach, which is a safe road system increasingly free of
death and serious injury. The road safety audit is a safety review used to identify all areas of a project
that are inconsistent with a Safe System and bring those concerns to the attention of the client so that
the client can make a value judgement as to appropriate action(s) based on the risk guidance provided
by the safety audit team.
The key objective of a road safety audit is summarised as:
‘to deliver completed projects that contribute towards a safe road system that is increasingly free of
Information
death and serious injury by identifying and ranking potential safety concerns for all road users and
others affected by a road project.’
A road safety audit should desirably be undertaken at project milestones such as:

concept stage (part of business case);

scheme or preliminary design stage (part of pre-implementation);

detail design stage (pre-implementation or implementation); or
Official

pre-opening or post-construction stage (implementation or post-implementation).
A road safety audit is not intended to be a technical or financial audit and does not substitute for a
the
design check of standards or guidelines. Any recommended treatment of an identified safety concern is
intended to be indicative only, and to focus the designer on the type of improvements that might be
appropriate. It is not intended to be prescriptive and other ways of improving the road safety or
operational problems identified should also be considered.
In accordance with the procedures set down in the NZ Transport Agency Road Safety Audit Procedures
for Projects Guidelines - Interim release May 2013 the audit report should be submitted to the client who
under
will instruct the designer to respond. The designer should consider the report and comment to the client
on each of any concerns identified, including their cost implications where appropriate, and make a
recommendation to either accept or reject the audit report recommendation.
For each audit team recommendation that is accepted, the client will make the final decision and brief
the designer to make the necessary changes and/or additions. As a result of this instruction the designer
shall action the approved amendments. The client may involve a safety engineer to provide commentary
to aid with the decision.
Decision tracking is an important part of the road safety audit process. A decision tracking table is
embedded into the report format at the end of each set of recommendations. It is to be completed by the
designer, safety engineer, and client for each issue, and should record the designer’s response, client’s
Released
decision (and asset manager's comments in the case where the client and asset manager are not one
and the same) and action taken.
A copy of the report including the designer's response to the client and the client's decision on each
recommendation shall be given to the road safety audit team leader as part of the important feedback
loop. The road safety audit team leader will disseminate this to team members.
Status: Final
September 2016
Project No.: 80508736 Child No.: 0103
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
1.2
The Road Safety Audit Team
This road safety audit has been carried out in accordance with the NZ Transport Agency’s Road Safety
Audit Procedure for Projects Guidelines – Interim release May 2013, by:

s 9(2)(a)
– MWH New Zealand Ltd - Hamilton Office (Team Leader)

s 9(2)(a)
- Opus International Consultants Ltd - Hamilton Office (Team Member)
The audit consisted of a day and night inspection. The audit was carried out during the afternoon of
Tuesday 23rd August 2016 in overcast conditions and was carried out in accordance with the Stage 3
1982
audit checklists as set out in the NZ Transport Agency’s Safety Audit Procedures for Projects document
(May 2013). Prior to carrying out the audit, the team met with the designers (Caleb McCarthy and Jamie
Minchington of BBO) to confirm scope, determine the issues and understand some of the decision
making processes that were considered during the detailed design phase.
Act
The main audit involved examining the detailed design drawings, driving through the site a number of
times in both directions and then inspecting particular parts of the roadway. A night time inspection was
also undertaken to understand delineation and reflectivity of the new barrier system, markings and
signage, and to ensure that the future proofing element (particularly adjacent to the Hamilton Section tie-
in) does not confuse drivers at night.
1.3
Report Format
The potential road safety problems identified have been ranked as follows.
The expected crash frequency is qualitatively assessed on the basis of expected exposure (how many
road users will be exposed to a safety issue) and the likelihood of a crash resulting from the presence of
Information
the issue. The severity of a crash outcome is qualitatively assessed on the basis of factors such as
expected speeds, type of collision, and type of vehicle involved.
Reference to historic crash rates or other research for similar elements of projects, or projects as a
whole, have been drawn on where appropriate to assist in understanding the likely crash types,
frequency and likely severity that may result from a particular concern.
The frequency and severity ratings are used together to develop a combined qualitative risk ranking for
each safety issue using the concern assessment rating matrix in Table 1-1. The qualitative assessment
Official
requires professional judgement and a wide range of experience in projects of all sizes and locations.
Table 1-1: Concern Assessment Rating Matrix
the Frequency (probability of a crash)
Severity
(likelihood of death or
serious injury)
Frequent
Common
Occasional
Infrequent
Very likely
Serious
Serious
Significant
Moderate
under
Likely
Serious
Significant
Moderate
Moderate
Unlikely
Significant
Moderate
Minor
Minor
Very unlikely
Moderate
Minor
Minor
Minor
While all safety concerns should be considered for action, the client or nominated project manager will
make the decision as to what course of action will be adopted based on the guidance given in this
ranking process with consideration to factors other than safety alone. As a guide a suggested action for
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each concern category is given in Table 1-2.
Status: Final
September 2016
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Table 1-2: Concern Categories
Concern
Suggested Action
Major safety concern that must be addressed and requires changes to avoid
Serious
serious safety consequences.
Significant safety concern that should be addressed and requires changes to avoid
Significant
serious safety consequences.
1982
Moderate
Moderate safety concern that should be addressed to improve safety.
Minor
Minor safety concern that should be addressed where practical to improve safety.
Act
In addition to the ranked safety issues it is appropriate for the safety audit team to provide additional
comments with respect to items that may have a safety implication but lie outside the scope of the safety
audit. A comment may include items where the safety implications are not yet clear due to insufficient
detail for the stage of project, items outside the scope of the audit such as existing issues not impacted
by the project or an opportunity for improved safety but not necessarily linked to the project itself. While
typically comments do not require a specific recommendation, in some instances suggestions may be
given by the auditors.
1.4
Documents Provided
Information
Detail design drawings were provided to the audit team for this RSA. The assessment has been broken
up into two distinct project works. The Waikato Expressway Safety Improvements drawings are listed in
Table 1-3 below. And, the Waikato Expressway Safer Speeds Classification drawings are also listed in
Table 1-4 below.
Table 1-3: List of Waikato Expressway Safety Improvements Design Detail Drawings Supplied for
RSA
Official
Revision
Drawing No.
Drawing Title
No.the SH 1 Waikato Expressway – Ohinewai Section
SRA-38D-CE-1001
A
Sheet Index and Locality Plan
SRA-38D-CE-1200 to
A
General Arrangement and Barrier Plans
1214
under
SRA-38D-CE-2901 to
A
Barrier Edge Details
2902
SRA-38D-CE-2911 to
A
Barrier Transition Details
2916
SRA-38D-CE-2921 to
A
Maintenance Access Bays
2927
SH 1 Waikato Expressway – Ngaruawahia Section
Released
SRA-38E-CE-1001
A
Sheet Index and Locality Plan
SRA-38E-CE-1200 to
A
General Arrangement and Barrier Plans
1220
SRA-38E-CE-2901 to
A
Barrier Edge Details
2902
Status: Final
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Revision
Drawing No.
Drawing Title
No.
SRA-38E-CE-2911 to
A
Barrier Transition Details
2916
SRA-38E-CE-2921 to
A
Maintenance Access Bays
2927
1982
SH 1 Waikato Expressway – Te Rapa Section
SRA-38F-CE-1001
A
Sheet Index and Locality Plan
Act
SRA-38F-CE-1200 to
A
General Arrangement and Barrier Plans
1210
SRA-38F-CE-2901 to
A
Barrier Edge Details
2902
SRA-38F-CE-2911 to
A
Barrier Transition Details
2916
SRA-38F-CE-2921 to
A
Maintenance Access Bays
2927
SH 1 Waikato Expressway – Cambridge Section
Information
SRA-38G-CE-1001
A
Sheet Index and Locality Plan
SRA-38G-CE-1200 to
A
General Arrangement and Barrier Plans
1202
Table 1-4: List of Waikato Expressway Safer Speeds Classification Detail Design Drawings
Official
Supplied for RSA
Revision
Drawing No.
Drawing Title
No.the General
SRA-38H-CE-2801
A
Signage Details Sheet 1 of 1
Rangiriri and Ohinewai Sections
under
Sheets 1 to 8
Signs Drawings
Ngaruawahia Section
SRA-38E-CE-2801 to
A
Signs and Markings Plan
2803
Te Rapa Section
SRA-38F-CE-2801 to
A
Signs and Markings Plan
2804
Released
Cambridge Section
Sheets 1 to 7
Signs Drawings
Status: Final
September 2016
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
1.5
Previous Audit
The Safety Audit Team are unaware of any other road safety audits being carried out on this project.
1.6
Audit Scope
This audit is a Detailed Design Safety Audit of the SH1: Waikato Expressway Safety Improvements (four
sections of the Waikato Expressway being Ohinewai Section, Ngaruawahia Section, Te Rapa Section
and Cambridge Section) drawings produced by Beca on behalf of Safe Roads Alliance.
1982
In addition, the Safety Audit Team was also requested to audit a Safer Speeds Classification for SH1:
Waikato Expressway for the following sections:

Rangiriri and Ohinewai Section,

Act
Ngaruawahai Section,

Te Rapa Section, and

Cambridge Section.
The objective of the Safety Audits are to improve severity of outcomes. Consequently, the Safety Audit
Team is tasked with looking for safety issues arising from the proposed works. The intent is not to be a
process of identifying minor non-compliances with industry guidelines, as there is a quick turnaround
between the implementation phase (part of which the safety audit sits within), and the construction
phase.
1.7
Disclaimer
Information
The findings and recommendations in this report are based on an examination of available relevant
plans, the specified road and its environs, and the opinions of the SAT. However, it must be recognised
that eliminating safety concerns cannot be guaranteed since no road can be regarded as absolutely safe
and no warranty is implied that all safety issues have been identified in this report. Safety audits do not
constitute a design review nor are they an assessment of standards with respect to engineering or
planning documents.
Readers are urged to seek specific technical advice on matters raised and not to rely solely on the
Official
report.
While every effort has been made to ensure the accuracy of the report, it is made available on the basis
that anyone relying on it does so at their own risk without any liability to the Safety Audit Team or their
organisations.
the
1.8
Client Review
Client review has been undertaken by James Hughes, National Design Engineer, and Graham Taylor,
National Network Optimisation Manager, both of whom are based in the NZ Transport Agency National
under
Office.
Some of the Safety Audit recommendations, Designer Responses and Safety Engineer comments have
not been implemented as part of the client decision. This is in no way a reflection on the quality of the
audit and responses/comments which, in our view, have been carried out appropriately.
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Status: Final
September 2016
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SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
2
Project Overview
This project is split into four sections along the Waikato Expressway for the Safety Improvements
element of the audit. The four sections are as follows:

Ohinewai Section – RP 0502/1.65 to 9.72

Ngaruawahia Section – RP 0527/0.54 to 0534/4.15

Te Rapa Section - 0534/3.9 to 0540/5.00

1982
Cambridge Section – 0557/3.42 to 4.60
These sections are currently subject to a 100km/h speed restriction although we are aware that the NZ
Transport Agency is considering an increased 110 km/h ‘Safer Speeds’ across significant lengths of the
study area. This forms part of the second assessment for this Safety Audit. In addition to the sections
Act
above, the Safer Speeds Classification also includes the Rangiriri Section from RP 0486/15.24 to abut
into the Ohinewai Section to the south.
The project comprises upgrading the existing road based on meeting the investment benefits as defined
by the Business Case for SH 1 Waikato Expressway. The Business Case project recommended a
preferred option which had been selected via a multi criteria analysis including factors such as actual
predicted Death Serious Injury (DSI) reduction, technical risk, financial constraints, timeframes and other
items.
Due to the risk profiles assessed, the treatments are likely based on a philosophy of ‘safety
management’ by carrying out the following site specific works:

Increasing sealed shoulder widths in parts (where a severe roadside risk exists).
Information

Widening the carriageway to accommodate a roadside Safety Barrier along the full length.

Providing and formalising maintenance access points/breaks along the continuous safety
barrier system.

Upgrading entranceways and closing entrances where required.
The location of those treatments were largely selected by using KiwiRAP and Road Protection Scores
(RPS) and on site investigation.
Official
The surrounding land use is generally a mixture of dairy, lifestyle blocks, sheep/beef farms and tourist
enterprises.
the
As a result of the information furnished to the auditors and subsequent site inspection we have noted
the following:

A number of active work sites associated with other committed Waikato Expressway works (i.e.
the Rangiriri and Huntly sections) that would directly impact on the proposal submitted.

A number of private entranceways which are still being retained as part of the Safety
Improvement projects. The retention of these private access-ways appear to be inconsistent
under
with the objectives of these works.
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Status: Final
September 2016
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
3
Safety Concerns and Recommendations
3.1
Waikato Expressway Safety Improvements
3.1.1
Ohinewai Section – Trailing Safety Barrier System from
Minor
Private Access-ways
1982
The current proposal for accessways relies on a W-Section arrangement (to RSB-2) curving from the
access-way gate, extending to overlap in front of the preferred WRB system at both private access-ways
at Station 1.78, 2.25, 2.88 and 6.33.
Act
This system effectively becomes non-gating immediately in front of the WRB terminal. This means that
if an errant vehicle strikes the curved component, the barrier is likely to fail and let the vehicle through
and/or decelerate rapidly resulting in the potential for occupant harm.
A desirable outcome is to present a leading end terminal and safety barrier system with an approved
taper in relation to the through lane such that an errant vehicle will be guided by the barrier system when
struck.
Recommendation(s)
Consider replacing the curved W-Section barrier system with the more forgiving WRB system. The WRB
taper could commence nearer to the access-way gate and immediately behind the prolongation of the
leading impact angle from the preceding trailing end terminal.Information
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
unlikely
minor
Designer
The designer notes the comments of the SAT. The space available does not allow
Official
response
for a flare of a WRB to provide continuous protection as a flare is also needed for
the diverge/'left in' movement.
The proposed Curved Rail Terminal is a standard NZ Transport Agency detail RSB-
2 as shown in the Technical Memorandum TM-2008. We consider this to be an
the
appropriate barrier treatment for this location.
Safety Engineer  Accept curved rail treatment as appropriate for these locations
comment
Client decision
Agreed
under
Action taken
3.1.2
General  -  Deficient  lateral  location  of  Safety  Barriers
Moderate
adjacent to Off-ramps
The drawings appear to locate new barriers with a 3m offset from the road side lane line through the
project, including off-ramps.
Released
At off-ramps it is essential that adequate sight distance is provided so that drivers have sufficient time to
see and react to the exit and diverge areas. This is particularly important in rural areas where drivers are
generally less alert than in urban situations.
The sight distance for an off-ramp treatment should be equivalent to ten seconds of travel time at the
operating speed of the expressway (equivalent to 300m for a Posted Speed Restriction = 100km/h or
330m for a Posted Speed Restriction = 110km/h).
Status: Final
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Failure to provide adequate sight distance may result in drivers diverging to the left late and either
running through the off-ramp nose (and into the barrier system), interacting with a following vehicle also
exiting the through road, or losing control of the vehicle.
We list the following as examples where sight distance measures significantly less than ten seconds:

Ohinewai Section: Ohinewai Northbound Off-ramp,

Te Rapa Section: SH 39 Southbound Off-ramp, and

Te Rapa Section: SH 39 Northbound Off-ramp,
1982
Recommendation(s)
Check sight distance to pavement marking is observed at start of diverge taper and at centre of off-ramp
lane adjacent to ramp nose. Ensure sight distance is maintained based on the relevant post speed
restriction adopted for the Waikato Expressway.
Act
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
occasional
likely
moderate
Designer
Ohinewai Section northbound Off-ramp sight distance = 305m. It is suggested that
response
the new barrier leading up to this interchange be located 3.5m offset from edge line
to provide ≥335m Sight distance. The drawings will be amended to include this
adjustment
Te Rapa Section SH39 Southbound Off-ramp sight distance = 288m (controlled by
Information
existing barrier) In this location the existing wire rope barrier could be relocated a
further 1.5m for a total offset of 4.5m from the edge line to achieve the appropriate
sight distance. This would require some re-grading of the berm area and possibly
some adjustment to the existing drainage swale alignment. The current barrier
location achieves a 288m sight distance which is equivalent to 9.5 sec. travel time at
110km/h. We request NZTA instruction to amend the existing barrier, berm and
swale in this location to achieve 10 sec. travel time at 110km/h.
Te Rapa Section SH39 Northbound off-ramp achieves a sight distance > 335m. No
Official
adjustment required
Safety Engineer  Agree with designer's proposed amendments to drawings for new barrier at
the
comment
Ohinewai northbound off-ramp
At Te Rapa SH39 southbound on-ramp it is preferred that the existing barrier is
relocated to achieve 330m (or 10sec travel time at 110km/h). Obtaining an cost
estimate for the necessary works is desirable.
We understand that the designer has checked the other off-ramps and no further
deficiencies were identified.
under
Client decision
Modern design practise is to design at the speed limit and not 10km/h above. This
reflects the significant reduction in speed profiles. Hence 305m is the appropriate
sight distance for 10 seconds of travel. 10 seconds is desirable for the safe
recognition of the approaching exit and the associated decision time. However we
are satisfied that a minor reduction to 9.5 seconds is acceptable.
Action taken
3.1.3
General  -  Deficient  WRB  laps  with  existing  Safety
Released
Moderate
Barrier Systems
The SAT has identified a number of deficiencies as it relates to WRB terminations with existing safety
barrier systems as follows:
Status: Final
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
1.
Proposed leading WRB and terminal lapping in front of an existing trailing barrier end terminal.
This arrangement places a terminal (and potential hazard) to oncoming traffic. A safer
alternative is to locate the leading terminal behind the existing trailing safety barrier end
terminal. The following areas are highlighted where this arrangement occurs:
o
Cambridge Section: Station 3.8 LHS
2.
Proposed trailing WRB and terminal laps behind an existing leading barrier end terminal. This
arrangement presents the same safety concerns as highlighted in (1) above. A safer alternative
is to locate the proposed trailing terminal in front of the existing leading safety barrier end
terminal. The following areas are highlighted where this arrangement occurs:
1982
o
Ohinewai Section: Station 7.88 LHS
o
Ohinewai Section: Station 8.11 RHS
o
Ohinewai Section: Station 8.98 LHS
Act
o
Ngaruawahia Section: Station 1.44 LHS
o
Ngaruawahia Section: Station 6.18 LHS
o
Ngaruawahia Section (Southbound): Station 0.67 LHS
o
Ngaruawahia Section (Southbound): Station 0.74 RHS
o
Ngaruawahia Section (Southbound): Station 2.47 LHS
o
Ngaruawahia Section (Northbound): Station 3.39 RHS
o
Ngaruawahia Section (Southbound): Station 3.74 LHS
o
Te Rapa Section: Station 1.25 RHS
o
Te Rapa Section: Station 2.23 LHS
Information
o
Te Rapa Section: Station 2.42 RHS
o
Te Rapa Section: Station 3.66 LHS
3.
Proposed WRB terminal laps in front of existing safety barrier terminals have insufficient lateral
clearance and/or lap length to ensure that a safety barrier performs as intended. The following
areas illustrate these deficiencies:
o
Ohinewai Section: Station 9.46 RHS (requires 1.2m separation, actual separation =
Official
0.9m)
o
Cambridge Section: Station 3.80 LHS (requires 1.2m separation, actual separation =
0.3m. Overlap length also deficient)
the
o
Cambridge Section: Station 3.81 RHS (requires 1.2m separation, actual separation =
0.6m. Overlap length also deficient)
Recommendation(s)
The Safety Audit Team requests that the designer considers:

commencing the proposed leading end WRB terminal behind existing safety barrier system,
under

terminating the proposed trailing end WRB terminal in front of existing safety barrier system. If
necessary, consider removing the terminal on the existing barrier system and extend to lap
behind proposed barrier system,

extending existing safety barrier system to terminate behind new barrier system with required
lateral clearances and overlap lengths observed.
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
Released
common
unlikely
moderate
Designer
1. The designer notes that lapping a WRB in front of a W-section barrier is not the
response
preferred option. The existing flare in the w-section barrier constrains the space for
the WRB to commence behind. We will adjust the design on the Cambridge section
to remove the existing flared leading/trailing terminals, install new straight
Status: Final
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SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
leading/trailing terminals and terminate the new wire rope barriers behind the w-
section barrier terminals as per our detail drawings CE-2911 and CE-2912. This is
similar to the arrangement shown on NZTA Technical Memorandum TM-2013 Nov
2014, Drawing RSB-7a.
1982
2. Our detail terminating the new WRB behind the W-section terminal is as
recommended on Drawing RSB-7a, NZTA Technical Memorandum TM-2013 Nov
2014.
3. Though to scale, barrier transitions on the GA Plans are diagrammatic and refer
Act
to transition details (CE-2911 through CE-2916) which detail the required
separations. In these cases, the barriers have 0.9m separation at the end of the w-
section and flare to 1.2m as recommended on Drawing RSB-7a, NZTA Technical
Memorandum TM-2013 Nov 2014
Safety Engineer  1. Agree that installation of new straight terminal ends as per drawings on NZTA
comment
Technical memorandum TM-2013 Nov 2014 is appropriate.
2. Agree that barrier terminals should be as per drawings on NZTA Technical
memorandum TM-2013 Nov 2014.
3. The details provide more accurate detail for construction of the barrier transitions
including the required clearances and overlap lengths.
Information
Client decision
Agreed that compliance with NZTA Technical memorandum TM-2013 Nov 2014 is
the appropriate approach
Action taken
3.1.4
Ohinewai Section - Deficient Armitage Road Diverge
Moderate
Official
The current Armitage Road Exit arrangement fails to protect an errant vehicle colliding with the heavily
vegetated roadside berm (immediately west of the proposed roadside leading end terminal) or beyond
through the exit break.
the
Recommendation(s)
Consider extending barrier system either side of the exit lane to beyond the ‘length of need’ measured
from the adjacent expressway. Consider a crash cushion at the gore point to protect vehicles from the
heavily vegetated roadside berm.
under
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
likely
moderate
Designer
The designer acknowledges the SAT comment. The designer suggests that the
response
vegetation behind the leading terminal could be removed for a distance of 30m to
satisfy the SAT concerns. It is noted that the vegetation in this location comprises
entirely of frangible flax bushes which in themselves provide an effective
deceleration medium and also act as an existing headlight glare screen for vehicles
Released  traveling south on Armitage Rd at night.
Though there will not be continuous edge protection at this point. Armitage Road is
expected to provide an appropriate flat, clear run-out length should a vehicle gate
through the leading terminal or the gap in the barriers, without the risk of striking
hazards.
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Consider the following:

Relocate all affected light poles to sit behind the new barrier system to achieve a dynamic lateral
clearance to the face of the pole. If this cannot be achieved, consider relocating poles beyond
the dynamic deflection distance in areas where there is a high personal and collective risk to
vulnerable users such as cyclists and pedestrians i.e. along the Te Rapa Section (where off-road
paths are in close proximity), and in the vicinity of interchanges.

Ensure all light poles are located behind the new safety barrier system.
1982
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
frequent
very unlikely
moderate
Act
Designer
For clarification, existing light columns that are positioned in front of new barrier
response
locations will be relocated behind the new barrier. The notes on the Drawings have
been improved to make this clear.
Light poles behind the barriers are to remain (even when within the deflection zone.
All these are frangible light columns. Currently on the Network, NZTA has accepted
shear base light columns within the deflection zone.
The above approach has been agreed in the 'Key Corridor Safety Retrofit Project
Scope Confirmation document between the Safe Roads Alliance (Jack Donaghy)
and the Agency (Graham Taylor) dated 5th August 2016.
Information
Safety Engineer  Would prefer that the existing light columns were relocated beyond the deflection
comment
zone, but recognise this deficiency is accepted elsewhere. Where possible these
columns should be relocated by the maintenance team as part of the renewal
programme or when damaged.
The maintenance team and contractor should be made aware of these locations to
ensure that the shear base columns are correctly torqued to operate as designed.
The designer should liaise with the maintenance team to ensure these actions are
Official
passed on.
Client decision
Acceptance of existing shear base or energy absorbing lighting poles within the
deflection zone is confirmed. Any new poles should be outside the tested deflection
the
zone.
Action taken
3.1.6
Te  Rapa  Section  –  Deficient  WRB  Break  for  Cyclists
Moderate
under
exiting/entering the Expressway
The current proposal relies on providing a narrow WRB break to allow cyclists to exit the expressway at
Station 3.32 RHS and 3.39 LHS.
The 5m wide break, in culmination with the WRB terminals either side, effectively provides a 25m long
gap in the safety barrier system where a vehicle is allowed to gate through the system. The gap further
exposes users on the adjacent shared path and fails to protect the occupants of an errant vehicle.
Recommendation(s)
Consider modifying the arrangement to be more consistent with that adopted on the Cambridge Section
Released
(ie North of Pickering Road Underpass) where a parallel barrier is implemented across the break and
behind the primary barrier system adjacent to the expressway.
Alternatively, consider providing cycle connectivity via an arrangement similar to Maintenance Access
Bay Type 3.
Status: Final
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Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
very likely
moderate
Designer
The designer agrees with the SAT comments. The design has been modified to
response
relocate the shoulder exit point further upstream by approx. 60m on each side, run
the cycle path parallel to the shoulder 2.0m behind the new WRB then connect back
to the existing cycle path. An approx. 70m length of new W-section barrier will be 1982
installed behind the new parallel section of cycleway to capture errant vehicles
exiting the carriageway through the barrier gap and to protect users of the adjacent
shared path. These adjustments will require modifications to the existing water
quality swales and the position of the cycle path exits from the carriageway
Act
shoulder.
Safety Engineer Agree that the barrier arrangement should be modified to provide a parallel barrier
comment
system.
There has been some negative feedback from cyclists about the tight alignment of
the arrangement adopted on the Cambridge section make it difficult or use by
requiring cyclists to significantly slow down. The proposed arrangement should be
reviewed in consultation with cyclists to ensure it is easily used by them.
Client decision
The requirement for cyclists to slow down over a short distance is a minor
inconvenience and needs to be weighed against the cost of a higher speed facility.
Agreed that the protection level needs to be improved due to the vulnerability of the
path users
Information
Action taken
3.1.7
General
–
Conflicts/Omissions
with
Committed
Minor
Expressway works in Progress
Official
The Drawings appear to advocate a number of safety barrier works which appear to be in conflict with
carriageway and safety barrier installations associated with committed works for the Rangiriri Section
and Huntly Section. In particular:the

The proposed works through the Ohinewai Section north of Station 2.25 is nearing completion.

The proposed safety Improvement works does not appear to be consistent with proposed four
laning works, and

The proposed works through the Ohinewai Section south of Station 9.30 is not consistent with
proposed four laning works currently under construction.

No improvement works are proposed through the Ngaruawahia Section north of Station 0.7 i.e.
under
no proposed safety barrier works along the southbound onramp from Taupiri and the adjacent
southbound onramp from Gordonton direction.
Recommendation(s)
Consider acquiring proposed works for the Rangiriri Section and Huntly Section and dovetail safety
improvement works into and/or over and above committed works.
Further, given that Huntly works could be completed sometime after the safety improvement works
(programmed for Year 2021), consider an interim treatment recognising the current (and/or future)
constraints of the temporary construction works on the network until such works are complete.
Released
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Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
occasional
unlikely
minor
Designer
The designer is in the process of attaining the designs for the Rangiriri and Huntly
response
sections of the expressway. The design will be amended prior to IFC issue
(expected in 2017) to provide continuity throughout the entire expressway when
these are received.
1982
Safety Engineer  Agree that design consistency design between the sections is important and confirm
comment
that the designers approach is acceptable.
Client decision
Act
Action taken
3.1.8
General – Maintenance Access Bay Conflicts
Minor
The Drawings appear to advocate a number of maintenance access bay works which appear to be in
conflict with the existing formation. In particular:

Ohinewai Section – Station 7.98 RHS: The leading end of the parallel guardrail (W-section) and
surrounding sealed access-way appears to conflict with the western approach fill embankment to
Information
Tahuna Road Overbridge.

Ngaruawahia Section – Station 4.17 LHS: The leading end of the parallel guardrail (W-section)
and surrounding sealed access-way appears to conflict an existing drain and headwall.
Not addressing these conflicts now may result in placing maintenance operators at further risk whilst
undertaking maintenance operations where it is unsafe to do so and/or place expressway through
movements at risk if maintenance operators are forced to undertake maintenance duties from the
adjacent shoulder. This is a Safety In Design (SID) element which requires to be addressed.
Official
Recommendation(s)
Consider the following improvements:
the

Investigate relocating opening further north to avoid embankment conflict,

Investigate relocating opening further north to avoid drain/headwall conflict.
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
unlikely
minor
under
Designer
Detailed topographical surveys have not been undertaken on this project. Best
response
efforts have been made to locate the proposed Maintenance Access Bays in an
appropriate location. Notes have been added to the drawings such that the detailed
locations of the Maintenance Access Bays are to be set out and confirmed with the
engineer on site during the construction process.
The designer has reviewed these locations and moved the Ohinewai maintenance
bay approx. 15m north as recommended.
The Ngaruawahia maintenance access bay is to be moved south to provide regular
Released  spacing between access bays and to better suit the topography.
Safety Engineer  Agree that the maintenance bays should be relocated to avoid the identified
comment
conflicts. .
Maintenance bays need to be carefully located as they are also used for speed
cameras so there is also a need to provide and maintain sight lines.
Status: Final
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Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
unlikely
minor
Client decision
Action taken
1982
3.1.9
Ngaruawahia Section – Deficiencies associated with
Moderate
Future Proofing Hamilton Section Integration
Act
The Drawings appear to highlight a number of deficiencies associated with locating the proposed safety
barrier in relation to the future Hamilton Section connection. They are as follows:

The proposed WRB location is based on the ultimate arrangement of the Hamilton Section.
However, there is no setting out to assist with determining the barrier alignment as offsets are
based on future edge-line locations. There is a risk that the Contractor may incorrectly interpret
these locations resulting in constraining current minimum safe stopping sight distances (SSD)
afforded along the existing alignment, or, increasing the risk that the future alignment may
require those barriers to be relocated once again.

Existing barrier between Station 5.75 and 5.85 LHS has been incorrectly labelled as WRB. The
actual barrier system consists of a W-Section arrangement.
Information

Existing rigid barrier terminating at Station 5.89 LHS illustrates a transition into a proposed
WRB. This transition cannot be achieved as shown

The proposed WRB between Station 6.43 to 6.51 appears to be located closer than 3m from the
existing edge-line (measures 1m at the closest point). The proposed location will adversely
affect forward SSD, is located with the current shy-line and will catch some drivers out should
they require to use the shoulder for breakdown or other purposes.

The existing median WRB between Station 6.35 and 0.06 has been incorrectly located.
Official
Consequently, the proposed barrier tie-ins are incorrect and will pose a hazard to vehicles if
constructed as shown.

The current wide shoulder along the northbound lane, between Station 6.1 and 0.6, is used by
the
NZ Police for enforcement purposes. The Safety Audit Team are unsure what provision has
been made along this section of the expressway. Future provision ensures that NZ Police are
able to continue with enforcement including checking HCV’s and their loads. The location should
be relatively future proofed recognising a Hamilton Section connection at this point. Refer to
Photo 1.

The northbound mainline (north of Lake Road Overbridge) consists of dual lanes and appears to
under
formalise a wide shoulder on the RHS by retrofitting a WRB some distance from the median
edge-line. The wide shoulder may encourage vehicles to pull off to the RHS as opposed to the
preferred and more natural LHS. Vehicles on the RHS through lane generally travel faster than
the LHS. A vehicle accelerating from the RHS at a relatively slower speed may surprise through
movements. This may result in through vehicles being forced to adjust speed and position to
accommodate those slower vehicles. It’s also important to note that the trailing end of the
proposed median WRB proposes to cross the northbound lane connection from the Hamilton
Section. This length could be reduced moderately to avoid rework associated with the Hamilton
Section tie-in works.
Released
Status: Final
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1982
Act
Photo 1: Police checking HCV’s
Recommendation(s)
Consider the following improvements:
Information

Provide set-out information for new safety barriers through future Hamilton Connection area,

Ensure trailing end of proposed WRB on the northern side is appropriately lapped in front of the
existing W-section barrier,

Ensure leading end of proposed WRB is appropriately lapped behind existing rigid barrier,

Ensure that the proposed WRB is located 3m minimum from the existing edge-line,

Review existing median barrier location and extend new WRB ensuring connectivity is
Official
maintained.

Review the need for shoulder space to be assigned for current Police Enforcement activities
through stakeholder consultation. If confirmed, ensure that the safety barrier system is optimally
the
located to future proof now, and, is located away from conflict points such as interchanges with
ample forward and rear sight distance.

Review the need for a wide shoulder along the RHS and reconfirm proposed WRB trailing end
terminal location.
Frequency
Severity
Rating
under
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
Designer
1. Set out information will be provided to the contractor in electronic format where
response
appropriate and via detail drawings and notes on the General Arrangement plans.
Much of the lateral barrier set out is fixed from off sets from existing edge lines and
existing barrier terminals. The general location of new barrier features such as
maintenance accesses are shown on the aerial photograph General Arrangement
plans but it is expected that these locations are to be set out and confirmed with the
engineer on site during the construction process.
Released 2. The existing barrier has been amended to show W-section. Transition details
have been updated accordingly.
3. The drawings have been amended to show a Type C Transition
4The barriers are shown 3.0m offset from future edge line.
5. Barriers in this location will be relocated during construction of the Hamilton
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SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
Section
6. The designer disagrees with these locations being used for police checks - the
photo shows non-compliant police activity (the police should sit nearer to the lane
than a vehicle he has stopped). The existing wide shoulder in this location is to  1982
accommodate the future Hamilton Section tie in. NZTA to confirm that HCV checks
are not a recommended practice on the Expressway and provision is/will be
provided elsewhere.
7. The existing safe hit posts will remain until the construction of the Hamilton
Act
Section to delineate the shoulder and discourage vehicles pulling off. The WRB is
installed in this location (though it will be relocated/removed in the future in order to
provide continuous edge barrier protection.
Safety Engineer  1-5. Agree with designer comments relating to provision of electronic setout data
comment
and minor changes to drawings.
6 The Transport Agency should discuss appropriate enforcement locations with
Police looking at the whole of the Expressway to ensure that Police can safety stop
vehicles when required.
7. Agree that vehicles should be discouraged from parking on RHS shoulder through
provision of safe hit posts.
Information
Client decision
Much of the edge protection provision in this area is under review as part of the
detailed design of the Hamilton Section. The Agency is an active member of that
alliance and will ensure fitness for purpose.
Police should not be carrying out heavy vehicle enforcement on an unprotected
shoulder and this will be rectified as part of the Weigh Right project. The installation
of safe hit posts on the median shoulder is not agreed as these are considered
Official
unnecessary and can also impede sight distance.
Action taken
the
3.1.10 General – OGPA Conflict with Cyclists
Significant
Drawing C2901 appears to be advocating a variable OGPA surfacing shoulder width (varying between
2.1m and 2.5m. Given that Ohinewai and Rangiriri Sections advocate a 1m wide painted shoulder bar
separation between the roadside trafficable lane and the shoulder assigned to cyclists, the OGPA lip will
be located in the centre of the shoulder available to the cyclist. Consequently this will present a hazard
under
to cyclists.
Recommendation(s)
Consider consistency across all sections of the expressway in terms of pavement marking and
application of OGPA on the shoulder. A desirable outcome is OGPA surfacing extended to the face of
the roadside barrier (or extend 2.5m absolute minimum from the adjacent roadside edge-line).
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
Released
common
likely
significant
Designer
The designer notes that the drawings were unclear with respect to the installation of
response
OGPA. OGPA is only to be extended where OGPA is already installed
(Ngaruawahia and Te Rapa). There will be no extension of OGPA to affect cyclists
on the Ohinewai Section as this section does not have OGPA surfacing installed.
Status: Final
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Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
likely
significant
Typical details have since been amended to show OGPA to be extended to 300mm
from the face of barrier where required.
Safety Engineer Cyclist safety is important and the providing OGPA to 300mm from face of barrier is
comment
supported.
1982
It is understood that the Cambridge Section will have OGPA applied this season, it
is desirable that this approach (OGPA to 300mm from face) is taken when surfacing
this section now to minimise the number of seal joints and potential rework.
Act
Client decision
Agreed that where OGPA is installed it is required to be continuous to end 500mm
from the barrier.
Action taken
3.1.11 General – Various Safety Barrier Deficiencies
Minor
The Drawings appear to highlight a number of safety barrier deficiencies. They are as follows:

A number of locations appear to locate the proposed safety barrier significantly beyond 3m from
the adjacent roadside edge-line. This is in conflict with the details illustrated under Drawing No.
Information
C2901 and C2092 which states a 3m offset to be observed. The following are a few examples
(but not an exhaustive list):
o
Te Rapa Section – Mainline: On approach and downstream of SH 39 Interchange in
each direction.
o
Te Rapa Section – Te Rapa Road Southbound On-ramp.
o
Te Rapa Section – Northbound Lane between Onramp and Te Rapa Road Overbridge
Official
o
Ngaruawahia Section – Te Rapa Road Northbound On-ramp.
o
Ngaruawahia Section – Mainline Station 1.83 to 2.02 LHS.
o
Ngaruawahia Section – SH 1B Northbound Off-ramp.
the

A number of locations appear to adopt an existing safety barrier closer than 3m from the
adjacent roadside edge-line. Continuous shoulder widths less than 3m may have safety
implications for on-road cyclists, breakdown vehicles and forward sight distance. The following is
one example:
o
Te Rapa Section – Station 1.70 to 1.85 RHS: Existing WRB located 2m from the
adjacent roadside edge-line
under

A number of existing median rigid barriers within the Ngaruawahia Section have no leading end
terminals. These terminals are located in close proximity to the existing median WRB and are
primarily installed to protect existing bridge piers within the median. Although shielded on
approach by a WRB, there is still a latent risk that an errant vehicle strike under WRB dynamic
deflection will result in rigid barrier contact and result in occupant harm. The Safety Audit Team
recognises that the proposed project works do not further aggravate the current situation.
Recommendation(s)
Consider the following remedial measures:
Released

If the design intent is to locate the proposed barrier system beyond 3m from the adjacent
roadside edge-line, then sufficient set-out should be provided by the designer to ensure that the
contractor set-out is consistent with the designer’s intentions and all doubt is removed.

Review the need to modify existing barrier systems where the lateral offset is less than desired.

Consider retrofitting the leading end of the median rigid barriers with a compliant terminal.
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Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
unlikely
minor
Designer
1. The designer notes that in some locations the aerial imagery is not completely
response
accurate and out of date. The drawings have been amended to show as accurately
as possible the location of the barriers on the GA plans. The Typical Barrier Details
drawings all clearly indicate the new edge barriers are to be located 3.0m minimum
1982
from the existing edge line.
2. The designer notes the comment of the SAT. Relocating existing barriers is
outside the agreed scope of the project and these barriers (typically 2.8-2.9m offset)
are not expected to pose a significant safety risk to justify changing the scope of the
Act
project. Where necessary, the taper to existing barriers will be compliant with
manufacturers and NZTA requirements.
3. The designer notes the SAT comments. This is outside the agreed scope of the
Project and the existing median barrier will remain in its current arrangement.
Safety Engineer 1. Agreed that typical details should be relied upon and show new edge barriers 3m
comment
from edge line.
2. As the offset is 2.8-2.9m we agree there does not appear to be a significant risk
from barriers remaining in their current location provided the necessary changes to
tapers are compliant.
3. The existing median barrier terminal should be upgraded to provide a consistent
Information
level of safety service along this strategic corridor.
Client decision
Agreed. While 2.8 – 2.9m offset to existing barriers may be acceptable. Offsets and
location of all barriers must be confirmed on site and installed at the most
appropriate offset. Upgrading the existing median barrier is not agreed as part of
this project.
Official
Action taken
the
3.2
Safer Speed Classification
3.2.1
General - Forward Sight Distance Deficiencies
Moderate
The Safety Audit Team has noted that with a lift in the posted speed limit, the 85%ile speeds
correspondingly increase. The proposed safety barriers are currently located to account for Stopping
under
Sight Distances, and merge/diverge sight distances at lane drops/gains and all off/on-ramps based on a
prevailing Design Speed = 110km/h. These sight distances are in place to ensure that a normally alert
driver, travelling at the design speed on wet pavement, perceives and reacts (and brake before reaching
a hazard in case of SSD) accordingly.
The high risk areas are where critical sight distances associated with a change of environment occurs
i.e. interchanges and at lane gains/drops.
Recommendation(s)
Released
Consider the following remedial improvements:

Review all proposed safety barrier offsets ensuring minimum critical sight distances are
achieved on the basis of a DS=120km/h (posted speed plus 10km/h).

Review existing safety barriers and ensure that there is sufficient sight distance and lateral width
to manoeuvre if required to avoid a hazard.
Status: Final
September 2016
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SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
Designer
Graham Taylor from NZTA National Office has indicated to the design team that
response
they are comfortable with a 210m SSD for the speed increase areas. Any discrete
areas where 210m SSD is not available, vehicle tail light height should be
considered as the object height.
1982
There are 3 discrete areas where the adopted 210m SSD has been compromised by
the installation of new edge barriers;
1. Ohinewai Sector;
Act
The northbound horizontal curve at the northern end of the sector between RP 3.2
and RP 2.85 has a minimum SSD of about 180m with a 3.0m barrier offset. A barrier
offset of about 4.75m from the edge line would be required in this location to provide
for 210m SSD. It may be possible to trim back the existing flax bushes glare screen
at the edge of the northbound carriageway in this location and attain a 4 to 5m
barrier offset on the inside of the curve. Notes will be added to the drawings for the
contractor to optimise the barrier offset in this location within the existing physical
constraints.
2.Ngaruawahia Sector;
There are 2 lengths of carriageway on the Ngaruawahia Sector that will have less
than 210m SSD with the addition of new edge barriers. These are the existing direct
Information
ramps at the future connection with the WEX Hamilton Bypass project. In the
southbound direction the SSD deficiency is at the right hand side of the 720m radius
curve which crosses over the future WEX Hamilton carriageway on a bridge
structure with a 3.0m shoulder width to the bridge and approaches barriers. The
approach barriers are at the edge of a high fill embankment so there is little scope to
increase the lateral offset without major earthworks and the barrier offset on the
bridge cannot be improved without widening the bridge.
Official
In the northbound direction the SSD deficiency is on the left side of the 720m radius
left hand curve adjacent to the future WEX Hamilton connection. There does appear
to be sufficient berm width in this location to position the edge barrier approx. 7.5m
from the northbound left side edge line to achieve the 210m SSD. The drawings will
the
be amended to show the increased off-set.
Safety Engineer  1. Agreed that barrier location should be optimised on site through vegetation
comment
trimming as proposed by designer
2. While desirable to improve SSD it is acknowledged that the existing constraints
make this difficult. As noted by the designer, National Office recognise that vehicle
under
tail lights can be considered as object height. Designer to confirm the available SSD
at these locations with tail light as object height
Proposed barrier in northbound direction should be relocated to achieve at least
210m SSD as proposed by designer.
Client decision
Where 210m SSD cannot realistically be provided, please advise what can
realistically be achieved
a.
For a 1.1m height of eye to 0.2m object
b.
For a 1.1m height of eye to a 0.8m high brake light
Released  Please also advise the available seal width for manoeuvring should we need to
apply Section 5.5.1 of AGRD Part 3 on the system ramps at the WEX Hamilton
connection.
Status: Final
September 2016
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SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
Action taken
3.2.2
General - Acceleration Distances on On-ramps
Moderate
1982
The Safety Audit Team has noted that acceleration distances are required to increase as a result of
lifting the expressway posted speed from 100km/h to 110km/h. The magnitude in additional acceleration
length is greatest where Interchange onramp lengths are short, ascending and compounded further
Act
where there is a high proportion of HCV’s.
By far the greatest affect are slower merging traffic into the LHS through lane adjacent to on-ramps. If
the differential speed is greater than 10 km/h, through traffic are forced to weave into the adjacent lane
to avoid the merging traffic. The weaving increases the risk for the LHS lane vehicle to interact with
either the adjacent RHS through lane or the merging traffic from the left.
The Safety Audit Team requests that all Onramp lengths are checked. In particular, the Safety Audit
Team has identified the following on-ramps presenting the greatest potential for differential merge
speeds:

Rangiriri Southbound On-ramp
Information

Great South Road Northbound On-ramp
Recommendation(s)
Review onramp lengths and ensure that ramp lengths do not encourage merge speeds with greater than
10 km/h differential.
Official
Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
the
Designer
The Rangiriri Southbound On-ramp, while it is included in the speed increase, is
response
currently under construction by others and is beyond the physical works scope of
this Project.
The Ohinewai to Te Rapa sectors include interchanges with on-ramps at Ohinewai,
SH18 Gordonton Road, Te Rapa Rd and Koura Drive. The lengths of the ramps
under
from the terminal intersection to the start of the 2% merge taper ranges from 300m
to 430m. The ramps are all on downhill grades and the mainline grades beyond the
ramp nose are generally flat with the exception of the Te Rapa southbound on-ramp
taper which is on a maximum uphill grade of about 1% . In all cases the merge
tapers are at least 265m long and all on-ramp configurations are in compliance with
the Standard Motorway and Expressway Exits and Entrances……. diagram, Figure
2.6A as shown in Motsam Part 3: Motorways and Expressways.
With an assumed entry speed of say 30km/hr, on a 3 to 4% down grade the length
required for a car to achieve a speed of 110 km/hr is about 350m. In all cases, with
ramp lengths noted above, this distance can be achieved either prior to or within the
Released merge taper area.
Austroads GRD Part 4C states that 'It is often impractical to provide very long entry
ramps and hence they should generally be in the range of 300m to 450m'.
In general all the on-ramps lengths and configurations, within the agreed scope of
works, comply with the current standards.
Status: Final
September 2016
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Frequency
Severity
Rating
Crashes are likely to be
Death or serious injury is
The safety concern is
common
unlikely
moderate
It is anticipated that NZTA National Office will reconfirm any design interfaces
between the Key Corridor Safety Retrofit Programme and projects currently in
construction once we have more certainty on the Key Corridor implementation
programme.
1982
Safety Engineer Where on-ramps are shorter than 350m, the edge barrier should be located to
comment
provide wider shoulders allowing additional space if conflict occurs between merging
Act
vehicles. This will require that the carriageway surfacing extends up to the barrier
face, this may require changes to the typical details
Client decision
Widening of the shoulder changes the ramp configuration and is not an acceptable
option. With the large number of trucks in the vehicle stream we will have a 20km/h
speed differential. In our experience, many cars enter the motorway at about
80km/h presumably due to motorist confidence levels. Given the relatively low
volumes on the expressway it is considered that there is ample opportunity for faster
vehicles to change lanes.
Action taken
Information
3.2.3
General - Various Sign Deficiencies
Minor
The following sign deficiencies were observed:

General - In many locations, large speed threshold signage is proposed to be installed within the
median i.e. Rangiriri Station 15,320m etc. Given that wind loading is likely to be a significant
factor in the design of the sign support system, the post may not be frangible in nature. If the
Official
post support is indeed a shear based system, the post may dislodge on impact and become a
potential hazard.

Rangiriri Section - The advanced warning speed limit signs at Station 15,150m (northbound)
the
may be obscured by the Bridge piers/abutments.

Cambridge Section – 100km/h speed threshold signage along the Southbound Onramp to
Cambridge West has been omitted.

Ngaruawahia Section – the advanced warning “80 km/h” speed threshold signs at Station 1.86
lack in appropriate sizing.
under

General – the proposed 110 km/h speed threshold signs at Station 4.71 (Te Rapa Section –
northbound) and at Station 0.73 (Ngaruawahia Section – southbound) are located at or near
areas where further decisions are required to support a change of environment ahead i.e.
diverge from single lane to dual lane etc. Imposing multiple decision making at these locations
may confuse some drivers. A desirable outcome is to separate these decisions further.
Recommendation(s)
Consider the following improvements:

Released
Consider the following:
o
Install additional median barrier protection to prevent vehicle interaction with threshold
signage in the median.
o
Undertake sign post design now to confirm requirements to support the sign panel at the
outset. This ensures that the contractor is not in a position to install a sign support which
might be detrimental to the outcome of a vehicle interacting with median signage.
Status: Final
September 2016
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
Relocate advanced warning signs prior to Te Kauwhata Over-bridge.

Install additional speed threshold signage for off-ramps in question.

Ensure that signing consistency and conspicuity is achieved by installing a 900x900 minimum
diamond plate size.

Relocate threshold signage to four seconds beyond the commencement of dual lanes.
Frequency
Severity
Rating
1982
Crashes are likely to be
Death or serious injury is
The safety concern is
infrequent
very unlikely
minor
Designer
Large threshold signs are shown in the median near the Te Kauwhata southbound
Act
response
Off-ramp, near Lumsden and Balemi Rd, either side of Kainui Rd, and south of
Tamahere. In these locations the median is 9m or wider and similar signs (which we
will replace or relocate) have already been installed in these locations. The
constructor will be required to install frangible posts in accordance with the RSMA
Compliance Standard for Traffic Signs. Similar sized signs have been installed with
frangible bases at the south end of the Te Rapa section.
Installing effective additional barrier protection around the signs will introduce a new
hazard to the median and significantly reduce the clear median width over a
reasonable length when compared to the point hazard of the sign. Installing
frangible sign bases will mean the sign represents a minor hazard. This would mean
the benefits and dis-benefits of installing additional barrier protection would be
significantly out of proportion to level of hazard the median signs represent.
Information
The warning signs at Te Kauwhata Road for northbound traffic are shown south of
the Te Kauwhata Road bridge.
100km/h off-ramp signage is now shown on the Southbound Offramp to Cambridge
West.
All warning signs are the large 1200x1200mm diamonds (or 900x900mm squares).
Official
The 110kph speed signage located at the north end of the Ngaruawahia Section,
there is no driver decision. The on-ramp forms a lane gain to the single lane to the
single lane main carriageway well in advance (600m approx.) of the two lanes
meeting. This also avoids any short lengths of 100kph.
the
The 110kph speed signage at the south end of Te Rapa is located at the
commencement of the two lanes on the expressway. The choice of one of two
parallel lanes is considered a minor decision which doesn't involve conflicting
movements and hence a minor risk..
Safety Engineer Accept signs located in 9m wide medians without additional barriers as minor
under
comment
hazard provided bases and poles are frangible.
Accept proposed layout at northern end of Ngaruawahia section as it avoids multiple
speed limits and is in advance of lane gain arrangement.
The location of the current temporary 80km/h speed limit on the Te Rapa section is
being reviewed. Designer to liaise with NZTA staff (Mike Pilgrim) to ensure that the
current review aligns with the location for the proposed 110/80km/h speed limit
change. Prefer that the location is downstream of the dual lanes commencing.
Client decision
Designer response and Safety Engineer comments agreed
Released
Action taken
Status: Final
September 2016
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4
Audit Statement
We declare that we remain independent of the design team, and have not been influenced in any way by
any party during this road safety audit.
We certify that we have used the available plans, and have examined the specified roads and their
environment, to identify features of the project we have been asked to look at that could be changed,
removed or modified in order to improve safety.
We have noted the safety concerns that have been evident in this audit, and have made
1982
recommendations that may be used to assist in improving safety.
s 9(2)(a)
Act
Signed
Date
6/09/2016
s 9(2)(a)
Principal Transportation Engineer, MWH New Zealand Ltd, Hamilton
s 9(2)(a)
Signed
Date
6/09/3016
Information
s 9(2)(a)

Principal – Road Safety, Opus International Consultants Ltd
Official
the
under
Released
Status: Final
September 2016
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5
Response and Decision Statements
System designers and the people who use the roads must all share responsibility for creating a road
system where crash forces do not result in death or serious injury.
5.1
Designer’s Responses
I have studied and considered the auditors’ safety concerns and recommendations for safety
improvements set out in this road safety audit report and I have responded accordingly to each safety
1982
concern with the most appropriate and practical solutions and actions, which are to be considered
further by the safety engineer (if applicable) and project manager.
Act
Signed
Date
[Designer’s name, qualification, position, company]
5.2
Safety Engineer’s Comments (if applicable)
I have studied and considered the auditors’ safety concerns and recommendations for safety
improvements set out in this road safety audit report together with the designer’s responses. Where
appropriate, I have added comments to be taken into consideration by the project manager when
deciding on the action to be taken.
Information
Signed
Date
[Safety Engineer’s name, qualification, position, company]
Official
5.3
Project Manager’s Decisions
I have studied and considered the auditors’ safety concerns and recommendations for safety
improvements set out in this road safety audit report, together with the designer’s responses and the
the
comments of the safety engineer (if applicable), and having been guided by the auditor’s ranking of
concerns have decided the most appropriate and practical action to be taken to address each of the
safety concerns.
under
Signed
Date
[Project Manager’s name, qualification, position, company]
5.4
Designer’s Statement
I certify that the project manager’s decisions and directions for action to be taken to improve safety for
each of the safety concerns have been carried out.
Released
Signed
Date
[Designer’s name, qualification, position, company]
Status: Final
September 2016
Project No.: 80508736 Child No.: 0103
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5.5
Safety Audit Close Out
The project manager is to distribute the audit report incorporating the decisions to the designer, safety
audit team leader, safety engineer, and project file.
Date: ……………………………….
1982
Act
Information
Official
the
under
Released
Status: Final
September 2016
Project No.: 80508736 Child No.: 0103
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Detailed Design Road Safety Audit Report
SH1: Waikato Expressway Safety Improvements, and,
Safer Speeds Classification
Appendix A
Drawings Audited
1982
Act
Information
Official
the
under
Released
Status: Final
September 2016
Project No.: 80508736 Child No.: 0103
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Document Outline