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Programme Business Case
Tinwald Corridor Study
10 March 2015
Approval
PREPARED BY: REVIEWED BY: ENDORSED BY: APPROVED BY:
Callum Wood
With input from
Neil McCann (ADC)
Stuart Woods Colin Knaggs
Ian McCabe – P&I
Canterbury BUDMT
ADC
The Transport Agency
PROJECT MANAGER TRANSPORTATION PLANNING
MANAGER
STAKEHOLDER PROJECT
SPONSORS
DELEGATED AUTHORITY -
STAKEHOLDERS
DATE: JAN 2015 DATE:FEB 2015 DATE: FEB 2015 DATE:
Revision Status*
REVISION NUMBER: IMPLEMENTATION DATE: SUMMARY OF REVISION
A 27/01/15 Draft for internal comment
B 19/02/15 Draft for Transport Agency/ BUDMT comment
C 27/02/15 Draft for ADC and working group comment
D 10/03/15 Draft for stakeholder comment and ADC
endorsement
Delete Revision Status Table on production of final version
Template Status
REVISION NUMBER: IMPLEMENTATION DATE: SUMMARY OF REVISION
Contents
Glossary of Terms ................................................................................................................................. 5
Executive Summary .............................................................................................................................. 7
PART A – THE STRATEGIC CASE ....................................................................................................... 8
1 Introduction .................................................................................................................................... 8
2 Partners and Key Stakeholders .................................................................................................. 11
2.1 Project Partners..................................................................................................................... 11
2.2 Key Stakeholders .................................................................................................................. 11
3 Strategic Assessment - Outlining the Need for Investment .................................................... 13
3.1 Defining the Problem ............................................................................................................. 13
3.2 The Benefits of Investment ................................................................................................... 14
4 Strategic Context ......................................................................................................................... 15
4.1 Organisational Outcomes, Impacts and Objectives .............................................................. 15
4.2 Alignment to Existing Strategies/Organisational Goals ........................................................ 16
4.3 Context with comparative networks and issues .................................................................... 16
5 Changes/Updates to the Strategic Case.................................................................................... 17
5.1 New Supermarket at South Street ........................................................................................ 17
5.2 New bridge designation ......................................................................................................... 17
5.3 Existing Strategic Assessment .............................................................................................. 17
PART B – DEVELOPING THE PROGRAMME .................................................................................... 18
6 Programme Context..................................................................................................................... 18
6.1 Geographical & Environmental Context ................................................................................ 18
6.2 Social and Community Context ............................................................................................. 18
6.3 Economic Context ................................................................................................................. 19
7 Demonstrating the Need for Investment ................................................................................... 20
7.1 Problems and Opportunities .................................................................................................. 20
7.2 Issues and Constraints .......................................................................................................... 20
7.3 Delay ..................................................................................................................................... 21
8 Stakeholders ................................................................................................................................ 23
8.1 Consultation and Communication Approach ......................................................................... 23
8.3 Professional Engagement Process ....................................................................................... 24
8.4 Consultation Feedback ......................................................................................................... 24
8.5 Next steps ............................................................................................................................. 25
8.6 Media ..................................................................................................................................... 25
9 Alternative and Option Assessment .......................................................................................... 25
9.1 Background ........................................................................................................................... 25
9.2 Initial assessment of Alternatives .......................................................................................... 25
9.3 Option discussion .................................................................................................................. 26
9.4 Assessment of options on Intersection Delay ....................................................................... 27
9.5 Discussion on second bridge (2026) key results .................................................................. 29
9.6 Discussion ............................................................................................................................. 29
9.7 Constraints and Dependencies ............................................................................................. 29
9.8 Key stakeholder feedback on alternatives and options ........................................................ 29
10 Programme Options Development and Assessment .......................................................... 31
10.1 Programme Development ..................................................................................................... 31
10.2 Process ................................................................................................................................. 31
10.3 Typical treatment example sketches ..................................................................................... 34
10.4 Do-Minimum Option .............................................................................................................. 35
10.5 Programme Assessment ....................................................................................................... 35
10.6 Cyclist and pedestrian specific comments ............................................................................ 36
10.7 Qualitative Assessment to deliver the benefits listed within the ILM .................................... 36
10.8 Discussion on the option results ........................................................................................... 37
11 Recommended Programme ................................................................................................... 39
11.1 Programme Overview ........................................................................................................... 39
11.2 Programme Implementation Strategy & Trigger Points ........................................................ 40
12 Recommended Programme – Assessment .......................................................................... 42
12.1 Programme Outcomes .......................................................................................................... 42
12.2 Programme Risk ................................................................................................................... 43
12.3 Value for Money .................................................................................................................... 43
12.4 Assessment Profile ............................................................................................................... 43
13 Programme Financial Case .................................................................................................... 44
13.1 Indicative cost........................................................................................................................ 44
13.2 Funding arrangements .......................................................................................................... 44
13.3 AffoRoadability ........................................................................ Error! Bookmark not defined.
PART C – DELIVERING & MONITORING THE PROGRAMME ......................................................... 45
14 Management Case ................................................................................................................... 45
14.1 Programme Governance and Reporting ............................................................................... 45
14.2 Stakeholder Engagement and Communications Plan .......................................................... 45
14.3 Programme Performance and Review .................................................................................. 45
Appendix A - Investment Logic Map .................................................................................................... I
Appendix B – Benefits Map ................................................................................................................. III
Appendix C – Location Map ................................................................................................................IV
Appendix D – Background Evidence to Needs ..................................................................................V
Appendix E – Background information to development of options .............................................VIII
Appendix F – Possible Treatments Discussion ...............................................................................XII
Appendix G – 2026 Level of service and actual volumes ..............................................................XIII
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Glossary of Terms
Abbreviation Term
AADT Average annual daily traffic
ADC Ashburton District Council
AEE Assessment of Environmental Effects
BCR Benefit-Cost Ratio
CAPEX Capital Expenditure
CBD Central Business District
CRLTS Canterbury Regional Land Transport Strategy
CVIU Commercial Vehicles Investigation Unit
D&C Design and Construct
DE Design Estimate
EEM Economic Evaluation Manual
EIR Environmental Impact Report
EOI Expression of Interest
EPA Environmental Protection Agency
FYRR First Year Rate of Return
GPS Government Policy Statement
HCV Heavy Commercial Vehicle
HNO Highways and Network Operations
HPT Historical Places Trust
ILM Investment Logic Map
IRS Investment and Revenue Strategy
ITS Intelligent Transport Systems
KPI Key Performance Indicator
LGA Local Government Act 2002
LTMA Land Transport Management Act
LTP Long Term Plan
MOU Memorandum of Understanding
NLTF National Land Transport Fund
NLTP National Land Transport Programme
NOR Notice of Requirement
NPC Net Present Cost
NZCID New Zealand Council for Infrastructure Development
NZTA The New Zealand Transport Agency (The Transport Agency)
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Abbreviation Term
NZTS New Zealand Transport Strategy
OPEX Operating Expenditure
PBC Programme Business Case
P&I Planning and Investment
PI Performance Indicator
PMS Project Management Services
PoPS Portfolio Procurement Strategy
PPFM Planning Programming and Funding Manual
PPM Principal Project Manager
PPP Public Private Partnership
PT Public Transport
PWA Public Works Act
RAMM Road Assessment and Maintenance Management
RFP Request for Proposal
RLT Regional Land Transport
RLTS Regional Land Transport Strategy
RMA Resource Management Act
RoNS Road of National Significance
SAR Scheme Assessment Report
SE Scheme Estimate
SH(#) State Highway (number)
SHAMP State Highway Activity Management Plan
SOI Statement of Intent
SSEMP Site Specific Environmental Management Plan
TA Territorial Authority
TDM Traffic Demand Management
TOC Total Outturn Cost
VAC Value Assurance Committee (formerly SSRC)
VMS Variable Messages Sign
WEBs Wider Economic Benefits
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Executive Summary
Part A: The Strategic Case
A Strategic Case was finalised in July 2014 following work on this project in 2013. This report confirms
the strategic context problems and benefits of a response identified in the Strategic Case.
Ashburton District Council (ADC) and the NZ Transport Agency (Transport Agency) are joint project
partners in this development of this Programme Business Case for the Tinwald Corridor (Ashburton River
to Maronan Road).
Tinwald is located in the southern part of Ashburton It is experiencing good growth in population and
it has a future development plan that is expected to accommodate for and encourage this growth.
A key driver for pursuing the strategic case is the current delays experienced for side road traffic at
most State Highway intersections along the corridor, and the corresponding loss of level of service are
predicted in 2016 particularly in morning peaks and worsening in 2026.
The second key driver is the severance issue born from having the state highway pass through the
middle of the Tinwald area. Pedestrian and cycling links need to be considered as the population grows
and areas are developed. The impact of cross movements due to severance is expected to have an effect
on the overall transport network performance if not planned for.
Investment is needed in the short term to enable solutions that will address delays at all intersections
and severance.
Part B: Developing the Programme
The options and programme recommended have been developed to address the objectives, issues and
problems identified in the benefit statement. In the longer term the Ashburton River Urban 2nd
bridge
will provide significant relief to most of the identified issues. A traffic model has been used that predicts
a variety of benefits (some notable and positive) for a range of different treatments depending on the
intersection.
All programmes investigated have similar strategic responses and relatively very close benefits. All have
a mixture of safety, severance and local road components. Many could support walkways and cycle-
ways.
Timing of any investment should be managed to recognise that while some areas of the Tinwald corridor
currently aren’t performing well for some periods of the day, most isn’t significantly compromised yet.
Notwithstanding, analysis has indicated that within 10 years this changes significantly, and therefore
investigation phases should continue with a view that any interventions (physical works) can be
introduced in a timely fashion.
An assessment profile of M/M/L has been determined for the recommended programme using the
Transport Agency’s Investment Assessment Framework.
Recommended Programme
The recommended programme has been developed internally and a timescale of 10 years has been used
due to the impacts being experienced. Activities are timed for when they are forecast to be needed.
The early activities include channelisation improvements at a number of key intersections that will assist
immediately with delay issues and look to include any needs for pedestrians and cyclists.
Medium to long term activities comprise of intersection improvements, cycleway and pedestrian
crossings and analysis of where best sited, intersection priority and potential speed limit changes.
A number of activities are proposed to be carried through to an Indicative Business Case for further
development. These are:
for a roundabout at Graham and other key intersection improvements on SH1 (Wilkin, Lagmhor and
Carters)
The longer term activities will be included as part of an internal Transport Agency review and update of
the programme business case in later phases.
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PART A – THE STRATEGIC CASE
1 Introduction
This programme business case (PBC) verifies the preferred programme of works along the traffic
corridor of SH1 in Tinwald, Ashburton that responds to the case for change outlined in the
Strategic Case. The proposal principally seeks to address a problem of safe and effective access
to SH1 for side road traffic in Tinwald.
Growth in the District with significant residential development both sides of the highway in
Tinwald, commercial centres along and at the end of the Tinwald corridor and general state
highway traffic volumes increasing are all contributing to efficiency and safety issues.
An earlier programme to address State Highway issues through Tinwald was identified as part
of the programme of works outlined in the Ashburton Transportation Study, 2008, (a joint study
commissioned by the New Zealand Transport Agency, the “Transport Agency” and Ashburton
District Council). Some have been implemented, but the remainder now need revisiting due to
the changing circumstance and analysis.
A Strategic Case was finalised in July 2014. It has not been formally endorsed by the HNO’s VAC,
but the approval process for strategic cases was unclear at the time, and it is expected the
programme business case will go through for VAC approval. The strategic case is verbally
supported by regional P&I, and the region BUDMT.
Part A of this business case revisits the strategic case and reconfirms the case for investment
following some further evidence collection, analysis and workshops with the key stakeholders
to support the programme development.
Part B discusses the development of the programme of works considered, the recommended
programme and its financial case
This PBC is supported by the following key documents:
Strategic Case – Tinwald Corridor Study, July 2014 – The Transport Agency and ADC
ADC District Plan designation (No. 208 ) of new Ashburton River 2nd
Urban Bridge
corridor , 2014
Tinwald SH1: Options Assessment (Traffic Modelling); Nov 2014; Opus
Tinwald Deficiency Assessment (Traffic Modelling); Oct 2014; Opus
A location map is shown in Figure 1 over page.
Page 9
Figure 1: Tinwald Corridor location map
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2 Partners and Key Stakeholders
Ashburton District Council (ADC) and the Transport Agency are joint project partners in this
development of this PBC for the Tinwald Corridor. Key stakeholders include Tinwald businesses,
the local Road Transport Association, Schools, Cycle clubs, Police, the developer community,
key Council staff and Councillors.
2.1 Project Partners
Ashburton District Council and the Transport Agency are jointly leading the Tinwald Corridor
proposal. They are partners in this process.
NZ Transport Agency: The Transport Agency is responsible for the planning, management and
operation of state highways through the Highways and Network Operations Group. This group
responds to the strategic direction of the Transport Agency as defined by the Governments
Policy Statement (GPS) for Land Transport Funding and the Statement of Intent.
Ashburton District Council: Ashburton District Council (ADC) is responsible for the land use
development planning in the Tinwald area and the local road transport network through its
district plan. Integration of the transport required to service land uses in the area and the
transport system is a key consideration for district councils.
2.2 Key Stakeholders
A number of key stakeholders external to ADC and the Transport Agency also have influence on
the project outcomes. They have been identified through discussion with Council staff and
through their engagement in previous processes such as the Ashburton Transport Study and
the Council’s Long Term Plan submissions. These organisations met as part of the workshops
held in Ashburton in 2014 for the Programme Business Case (PBC). Their anticipated role, area
of expertise and interest in the project is summarised below:
Ashburton Business Association: The business community will be interested to
represent the potential traffic related impacts on both the immediately adjacent and
affected businesses, as well as the wider Ashburton business community. They are a
valuable contributor in understanding the nature and scale of the problem and the
potential benefits of investment in the area.
Local Businesses and Residents: These stakeholders are the most directly affected
groups. There is one local residents group, the Ashburton Citizens Association which
represents residents from across all Ashburton. There is no local business group
representing the immediately affected businesses.
Mid-Canterbury Road Transport Association: The working knowledge of the day-to-
day operation of the transport network as used by the freight industry, as understood
though their collective membership of operators, is highly valuable in understanding
the nature and scale of the problem and the potential benefits of investment in the area.
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Canterbury AA: The Canterbury AA regularly provides useful input to transport
proposals, representing their membership of private vehicle owners. The AA can be a
very useful contributor and partner in seeking out the views of its membership through
their communication channels. This could be highly valuable in understanding the
nature and scale of the problem and the potential benefits of investment in the area.
Lake Hood Developments: The Lake Hood development is a significant residential
subdivision (470ha) located at Lake Hood, about 13 km south-east of SH1 (Tinwald). It
has already sold sections in eight previous stages, and will continue to contribute traffic
demand to the SH1 intersections from the east. The views of this significant
development group is useful in providing insights and values of developers of the land
flagged for re-zoning and development both east and west of Tinwald.
Tinwald Primary School: Tinwald Primary School has pupils that travel to school from
both sides of SH1. The safety of this travel and the opportunities for active travel modes
for the school travel are key aspects of the school’s interest in the issue, as well as
potentially providing a very useful mechanism to gain an understanding the nature and
scale of the problem and the potential benefits of investment in the area from the
perspective of their school community.
Cycle club: both sides of the State Highway currently has cycleway lanes marked. Any
changes need to be made in consultation with this group and the workshops have
identified work packages that are suggested on both the state highway and local roads
that will improve user experience, overall use and safety of cyclists and pedestrians
Emergency Services (Fire Service, St John’s Ambulance and Police): These groups have
key interests and information regarding the corridor from the perspectives of ensuring
that they can maintain excellent response times to and from the Tinwald community,
and the safety/crash issues experienced at the SH1 intersections.
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3 Strategic Assessment - Outlining the Need for
Investment
Inputs from the ILM workshops have allowed the problems and benefits to be identified and
compiled into the process.
Growing population and developments along this corridor, measured AADT and intersection
survey counts, plus modelling of the network have provided the evidence base for corridor
performance expected now (2016) and in the future (2026) for a range of intersection treatments
and scenarios.
Significant delays for side road traffic at State Highway intersections and a corresponding loss
of level of service are predicted in 2016 and worsening in 2026. The traffic model predicts a
variety of benefits (some notable and positive) for a range of different treatments depending on
the intersection. More importantly the model highlights where little benefit is gained.
3.1 Defining the Problem
A facilitated investment logic mapping workshop was held with key stakeholders in 2013.
The ILM process identified and agreed the following key problems. In brackets are the relative
weightings assigned to the problems in terms of the importance of addressing the problems.
Problem 1
An historical lack of inter-agency integrated road network planning
has led to impacts on development in Tinwald
Problem 2
Limited travel and transport options has led to poor customer
satisfaction
Problem 3
State Highway traffic is leading to increasing severance and access
issues in Tinwald.
The Investment Logic Map is attached as Appendix A
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3.2 The Benefits of Investment
The potential benefits that could be realised through investing to address the identified
problems were identified in the benefits workshop held in 2013.
Benefit 1
Early awareness, understanding and support of projects
/programme by customers and stakeholders
Benefit 2
Effective staged investment programme for network and private
investment continuity
Benefit 3
An effective and efficient integrated transport system operates in
Tinwald
Benefit 4 Improved balance for accessibility and amenity of all users
Benefit 5 Improved Safety
The Benefit Map is attached as Appendix B. The Benefit Map has been completed with the
addition of potential investment KPI’s with associated measures and targets.
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4 Strategic Context
4.1 Organisational Outcomes, Impacts and Objectives
The Tinwald Corridor Business Case, as a proposal, will be developed under the overarching
integrated planning approach to land transport investment guided by the GPS, Transport
Agency’s Statement of Intent, and the Investment Assessment Framework.
The corridor business case will respond to the organisational objectives in the following ways:
The Transport Agency has classified the state highway through the area as a national highway.
National highways have a set of performance metrics that are desirable, but that can be heavily
influenced through urban areas that they cross through. These are:
provide excellent journey times and journey time reliability
have no capacity constraints
assist more efficient freight supply chains, through efficiently and effectively catering for
significant freight traffic
form part of a safe, secure and resilient road network, including key routes to major
ports and airports
The Canterbury Regional Land Transport Strategy (CRLTS) does not explicitly mention any
projects nor key issues in Ashburton. Nevertheless the CRLTS expects a series of outcomes if
the Vision and Objectives are achieved, including
Improved land use and transport integration.
Reduction in fatal and serious injuries for all modes.
Improved health from increase in time spent and more people travelling by active means.
Improved journey time reliability on the strategic transport network and key freight
routes.
Connectedness is enhanced.
Ashburton District Council has adopted the Future Ashburton Development Plan as a blueprint
for the development of the district in the future. It contains information on and responses to
the impact of predicted district growth. The Plan includes proposed changes to existing zoning
in a number of areas to provide additional land for future residential, commercial and industrial
land needs. This includes medium and low density residential growth areas in Tinwald on both
sides of the state highway as well as investigating additional commercial areas adjacent to it.
The plan also proposes to review highway access points, due to the urban growth in Tinwald
and the ongoing traffic growth along the state highway. Implementing the plan for the future
development of the district is seen as a long term project for the Council and work will need to
be prioritised and staged over many years.
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Ashburton District Council has adopted an Ashburton Transportation Study (joint study with the
Transport Agency) that provides a strategy and programme of measures to optimise the
Ashburton transport system.
The study presents a series of principles upon which the programme of measures was based,
some of which are relevant to this Strategic Case:
Principle 1: provide an integrated approach to land use and transportation planning so
as to minimise the adverse effects of one on the other;
Principle 2: provide safe and efficient access to SH1 at Tinwald
Principle 3: Encourage and enable safe use of alternative modes such as walking and
cycling.
Principle 6: Reduce side friction and conflict between through and local vehicles on
State highway arterials.
This study received strong views from the local community regarding access to the state
highway, and travel between Tinwald and Ashburton for local residents and businesses. The
Council has received these views, and accept them as a significant issue to address.
4.2 Alignment to Existing Strategies/Organisational Goals
The Strategic Case report demonstrated how the Tinwald Corridor Study project aligns with
strategic objectives and direction of the GPS, National State Highway Strategy, Safer Journeys
Action Plan 2013-15, Transport Agency Statement of Intent 2012-15, and SHAMP 2012-15 as
well as regional and local strategies and plans, such as the Ashburton District Development Plan,
the Ashburton District Plan, the Canterbury Regional Land Transport Strategy, and the
Ashburton Transportation Study. Refer to that report for the full reference table of information.
4.3 Context with comparative networks and issues
The State Highway traffic volumes in excess of 22,000 AADT near the existing Ashburton River
bridge are of a comparable volume to SH6 and SH6a at Frankton. Similar difficulties are also
experienced there with the inability to right turn and delay problems at side roads and property
accesses in general.
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5 Changes/Updates to the Strategic Case
Some nearby changes outside the study area were noted during 2014 that have been modelled
in the 2014 PBC traffic model analysis so that early indications of any effects and the sensitivity
of them could be understood. These include a new supermarket and signals at SH1/South Street
to the immediate north of the study area and the Ashburton River 2nd
Urban bridge designation
that would have effects on the local road and State Highway traffic.
5.1 New Supermarket at South Street
During 2014 and the formulation of this PBC, a resource consent application was received by
Council for a major supermarket development immediately to the north of the current Ashburton
river bridge. Associated with this application is the proposal of the developer to construct
signals at the SH1/South street intersection as a condition of the application. Given the
likelihood of this application being favourably assessed the project team has modelled signals
at this intersection for the 2026 model during this PBC analysis.
5.2 New bridge designation
In 2014 the approval and granting of a designation for the 2nd
Ashburton bridge was gained.
The earliest possible opening of this is 2026 and hence the project team has modelled this
bridge taking effect from the 2026 model as part of the sub options for 2026.
5.3 Existing Strategic Assessment
The existing strategic assessment is confirmed from the previous as M/M/-.
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PART B – DEVELOPING THE PROGRAMME
6 Programme Context
Tinwald is separated from the Ashburton town centre by the Ashburton River, and has significant
transportation issues due to it straddling State Highway 1 and the adjacent main trunk railway
line. Schools in the area and immediately adjacent to the study area along with a retirement
home are considerations. It is classified as a low socio-economic area of Ashburton, containing
5580 residents. While the area of study is urban the traffic generated is heavily influenced by
rural activities, rural development and rural vehicles. In addition due to the lack of public
transport and distances involved in this rural based community, significant reliance is placed on
private vehicles for travel needs.
6.1 Geographical & Environmental Context
Tinwald is the name of the area of Ashburton south of the Ashburton River, home to
approximately 5580 residents1
(estimate on 2013 data from census).
Tinwald straddles State Highway 1 for about 2.7km from the bridge to the South end with the
Main Trunk Railway Line adjacent to it. The railway line and State Highway cause significant
severance between East and West Tinwald.
A 330m two-lane bridge connects Tinwald to the rest of Ashburton. This bridge is approaching
capacity2
and investigations into building a second bridge are currently progressing with the
designation granted in 2014 but construction no scheduled until circa 2026.
6.2 Social and Community Context
Tinwald residents have a lower average income than the rest of Canterbury, and have a high
proportion of older people, with 17% over 65, compared to 14% in the Canterbury region (2006
data).
The Ashburton District is one of the fastest growing districts in New Zealand, behind only
Selwyn, Queenstown-Lakes, and Waimakariri from the latest census data (2013).
Lake Hood
The Lake Hood development at the South Eastern side to Tinwald, arrived at from the state
highway via Graham St, has been an area of significant rural residential growth with the new
District Plan (chapter 7) 3
allowing a further 350 residential lots to take the total to 500. This
new District Plan became operative in August 2014.
Pedestrian and cycle specifics
The 2.7km long urban area contains only one pedestrian crossing across the highway, no
signalised intersections, and four public railway crossing locations.
The movement of mobility scooters around the northern section of this study area and the
retirement home located on Carters Terrace is a particular point to note.
In addition the Tinwald area has school children who attend various primary schools and
Ashburton intermediate and Ashburton College on the North side of the bridge. While this is
outside this study area the movement of these pupils as pedestrians and cyclists is part of this
project and is a particular focus area around the Northern intersections (e.g. SH1/Carters), the
bridge crossing and how the local roads and cycle lanes function to cater for this group.
The movement of pedestrian traffic, especially children walking and on scooters, in the school
week, and in weekends, along the state highway and how they feed to it via and along the local
1 The ADC community planning document estimated 18% of the total Ashburton Population in Tinwald 2 (2013 AADT of 22,327 vehicles per day) 3 Chapter 7: ADC District Plan
Page 19
streets needs to be well understood for any solutions to be optimised. The investigation of
where pedestrian crossings are best located is part of the integrated solutions required.
6.3 Economic Context
Ashburton is surrounded by productive farmland which has traditionally formed the basis of its
economy. In 2011 agriculture, forestry and fishing made up 26% of the local economy. This was
supplemented by manufacturing (18%), retail (12%), and business and property services (10%).
The Ashburton economy is growing quicker than the national economy, principally due to the
success of the dairy industry. In 2011 the GDP grew 2.1% (national growth of 1.6%) and in the
decade from 2001 to 2011 it averaged 2.8% p.a. growth (2.3% p.a. nationally).
Page 20
7 Demonstrating the Need for Investment
Investment is needed in the short term to enable solutions that will address delays at all
intersections and severance. Any option and programme should be developed to address longer
term objectives and other developments, and integrated with safety outcomes for all users
7.1 Problems and Opportunities
The key problem identified, which is already occurring on the network, is delays at intersections.
This is at most intersections at both morning and afternoon peaks. The 2016 model predicts all
intersections having low levels of service (LOS) for side road traffic and by 2026 the delays are
significant.
The timeline for changing any significant land use driven solution is very long making it an
impractical short term solution and similarly the do nothing/ do minimum is not acceptable due
to the increases in side road delay and growing severance from high state highway traffic flows.
The second bridge option is the likely long term solution that largely resolves a proportion of
traffic volume for entry onto the state highway – but not entirely resolving delays by the time
that option happens. A second bridge will cause a significant amount of re-routing of traffic
given the different opportunities then available.
Therefore solutions that are both practical and achievable in the short term (pre-2nd
Ashburton
River urban bridge) without compromising mid/long term objectives and outcomes on the
network are the most desirable.
The second key problem is the severance of the community both sides of the highway makes it
difficult for cyclists, pedestrians and elderly (mobility scooters) to travel to schools and shops
so an integrated solution is required that takes into account these specific user groups at the
same time as any intersection improvements.
The opportunity exists now to implement improvements in a staged manner that integrate the
state highway with the local roads that will also cater for future developments such as increasing
Lake Hood development and a second Ashburton River 2nd
urban bridge long term.
7.2 Issues and Constraints
‘Issues’ or uncertainties include when a second urban Ashburton River bridge would be
constructed but modelling of this has given direction as to which suggested improvements are
aligned with this or not.
The growth of Lake Hood has been sufficient to clearly indicate that this is developing into a
major residential hub and the question only remains how soon, not if, it becomes bigger.
Any new major land-use development in the Tinwald area would most likely affect the network
efficiency negatively due to the current capacity issues.
A constraint on the layout of some options is the proximity of the railway line to the West side
of the state highway. This is particularly evident around Lagmhor Street where the lack of room
for any major improvement option to be realistically considered is a major constraint with the
railway to the West and significant operating businesses to the East.4
Some consideration is required with respect to the green space on the immediate West of the
highway. While it appears on first sight to be an attractive solution to use more of that for
highway widening (e.g. for through lanes on seagull and merge lane options or relocating the
cycleway off the state highway), this area does contain green space and trees that would be lost.
Tinwald is also a relatively low lying area and stormwater retention and flows paths around this
4 Page 10; Transport Agency 2009: SH1 Agnes St/Lagmhor Road intersection upgrade – Tinwald PFR report
Page 21
area are critical. Council does not want to lose too much of this area so as to retain future
stormwater retention basin options.
Another constraint is funding. All projects are required to be economically justified and major
works are not likely to achieve that threshold in Tinwald compared to other areas of New Zealand
when competing for the funds from the NLTP.
7.3 Delay
The following tables have been derived from the 2014 analysis of the updated traffic model and
show the Do Minimum Level of Service for intersections through Tinwald for 2016 and 2026
modelled years and the morning peak, business hours and evening peak periods. Additional
information regarding actual numbers of vehicles turning at many State Highway intersections
is provided in Appendix G. This is important context information showing the actual number
of vehicles affected and in several locations poor levels of service occur where there are only a
small number of vehicles. Notwithstanding the poor levels of service also appears to have
resulted in some drivers finding alternative and longer routes of less delay.
It is important to note that the delays at State Highway intersections are mainly for vehicles on
the local road network when accessing the state highway at the key intersections.
The overall level of service across all time periods has deteriorated to LOS F as modelled to
2026. When the Ashburton River 2nd
urban bridge crossing is constructed the level of service in
the am and pm peak periods are still LOS F at two of the four key intersections.
The do minimum for each intersection is noted in the following tables and range from B-F in
2016 with deterioration from there to be mostly F in 2026.
The acceptable or target level of service for the key intersections is LOS C5
Considering the target of LoS C or better, it can be seen in the following tables that although
there are some issues in the 2016 results, the need to intervene grows significantly by 2026.
Table 1: Level of service (LOS) band widths
5 Canterbury Regional Land Transport Strategy
Page 22
The 2016 Do Minimum models the existing strategic roads throughout Ashburton. The 2026
model is identical with the Do minimum of the signalised intersection at SH1/South Street.
For simplicity only the four main intersections (by volume) are shown here, the other 3 modelled
(Johnstone St, Hassel Street and Maronan Road) can be viewed in full in the Opus Options
assessment report. In general they follow similar trends to that shown for the main intersections.
Intersection
2016 SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
AM IP PM AM IP PM AM IP PM AM IP PM
Do Minimum C B C C B C E C F E C F
Intersection
2026 SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
AM IP PM AM IP PM AM IP PM AM IP PM
Do Minimum F D F F D F F F F F F F
Intersection
2026 Model SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
OPTION 3: 2nd
river
bridge with:
AM IP PM AM IP P
M
AM IP PM AM IP PM
Do min (existing
network)
C A C D B D F D F F C F
Table 2: Model and level of service change for Do Minimum
Page 23
8 Stakeholders
A targeted consultation process has been undertaken with a wide group of diverse key
stakeholders invited to participate in the workshops held through the Programme Business Case
phase. Good feedback was received from all involved who stated the collaborative process
enabled them to fully understand the issues and the process.
A wider group of less directly affected stakeholders has also been identified and they have had
an opportunity to provide input prior to completion of this PBC.
Media interest has been positive with all local outlets picking up the project media releases and
publishing information.
8.1 Consultation and Communication Approach
The process for identifying key stakeholders involved the Transport Agency and ADC project
staff in fortnightly conference calls and specific project meetings narrowing down whom in the
community could best represent a broad cross section of users that would provide a variety of
knowledgeable viewpoints. The workshops were attended by the following representing their
interest group as noted:
Stakeholder attendee as participant Representing
Cr Darryl Nelson ADC Councillor
Cr Stuart Wilson ADC Councillor
Cr Alasdair Urquhart ADC Councillor
David Harford (Urbis Ashburton Ltd) Developers
Gary Clement Tinwald Business representative
Peter Livingstone Principal Tinwald School
Hillary Boyce Ashburton Principal Assn
Diane Rawlinson Ashburton Citizens Assn
Jim Crouchley NZ Road Transport Assn regional representative
Rob Hooper Chair Tinwald Cycle Club (& Police)
Mary McConnell (ADC) Planner
Andrew Guthrie (ADC) Assets Manager
Brian Fauth (ADC) Contracts Manager
Colin Knaggs (Transport Agency) State Highway Manager
The following project team and support staff attended:
Project team member Representing
Neil McCann (ADC) Group Manager
Crissie Drummond (ADC) Support Officer
Matt Barnes (Transport Agency) Transport Agency Facilitator
Ian McCabe (Transport Agency) Planning & Investment Manager - Southern
Stuart Woods (Transport Agency) Acting Transport Planning Manager
Callum Wood (Transport Agency) Project Manager
Page 24
8.2 Interested Parties
The following are other groups identified as potentially affected parties at a less directly affected level
and they have received information from the workshops as part of the overall consultation. i.e. not
directly involved in the workshops but given the information all received and the opportunity to comment
on it. These are:
Federated Farmers
AA
NZ Heavy Haulage Assn (Jonathan Bhana-Thomson, Chief Executive, Wellington)
Emergency Services (NZ Fire Service, St John, NZ Police)6
.
Agricultural contractors
Grey Power and Terrace View Retirement Village on Carters Terrace
School bus coordinator (Mid Canterbury Bus Services)
Lake Hood representative/developers
Café Time (local Tinwald business)
Child’s Play Pre-school (local Tinwald business)
Lushingtons (local Tinwald business)
8.3 Professional Engagement Process
The main component of the professional engagement process focused on first identifying
programmes and then option development within those programmes at the two workshops held
through this Business Case. Associated with this was pre-circulated material and stakeholder
review of subsequent notes and reports. Limited one on one engagement occurred as required
for some stakeholders.
This was facilitated by the following Transport Agency staff: Matt Barnes, as facilitator; Stuart
Woods (background and context), Callum Wood (summaries of traffic model analysis), and Neil
McCann of ADC, (local context).
8.4 Consultation Feedback
Business representatives (and the entire stakeholder group) are in agreement that while there
are businesses along this corridor, there will not be any major effects on them as already they
are largely impacted by either the inability to turn right from side streets (due to no gaps in the
traffic) or restricted by parking restrictions, (eg intersection of Wilkin Street outside the bakery
where parking is provided to the rear of the business).
Discussions on parking included the current availability of parking on the North bound side of
state highway 1 for parents to use for drop off and pick up of children from the pre-school on
the opposite side of the state highway. The stakeholder group thought that restricting these
parks or losing them to enable highway widening would improve safety.
Peter Livingstone spoke to the group regarding his views on how the school children arrive at
the highway from residential areas on both sides and in particular how the north end for crossing
over the bridge is not catering for them (safety and severance topics). He also observed that
students using scooters are not well catered for on the local roads or crossing the state highway
and that weekends are also high peak times for children travelling from residential areas (both
sides) to the shops along the corridor.
6 note Rob Hooper attended the workshops as the cycle club rep and is also a member of the local Police
Page 25
Increasing use of mobility scooters in the Carters Terrace area, the inability for two scooters to
pass on the bridge cycle lanes and general lack of cycleway definition (used by scooters as well)
in the Northern end of Tinwald was discussed.
The working group were unanimous in agreement that the existing pedestrian crossing between
Lagmhor and Graham should be investigated to be moved South to the Graham /Jane Street
block due to safety concerns of vehicles exiting Graham and the quantity of over-dimension and
large vehicles turning at this intersection (right onto SH1) directly in front of the pedestrian
crossing.
8.5 Next steps
Where adjoining, the directly affected businesses will need to be closely involved in any
subsequent design process due to the effects from specific intersections improvements on the
highway or roads adjacent to them. Residences will have slightly different needs on some
aspects.
Similarly heavy transport, the retirement home and school user groups will have specific views
and needs on any detailed designs.
8.6 Media
As part of the PBC phase media statements have been released that have communicated the
broad process being developed by the project partners. A small number of local newspaper
articles have been printed on the project, mainly from the project team media release but also
other general commentary, and all in a neutral tone. In addition project information has been
provided on the ADC website. This approach will be continued, and may be expanded upon
when any general public consultation occurs in later phases.
9 Alternative and Option Assessment
9.1 Background
Previous studies of this corridor investigated and suggested traffic signals at Agnes/Lagmhor
without adequately defining the issues and full range of strategic responses and timing due to
the previous scope. This Business Case process is addressing that via the more structured and
holistic approach of the business case.
9.2 Initial assessment of Alternatives
The first PBC workshop (September 2014) discussed a number of themed programmes
(numbered from 1-7), that are best described as follows to address the issues identified to date:
Programme 1: Do minimum – basic maintenance, manage parking, markings, signs and
accessways
Programme 2: Safety approach which might include for example some central medians (wire
rope), parking management, cycle separation (in berms), separate lanes, speed reduction,
lighting etc
Programme 3: provision of alternatives to private vehicle which might include; TDM, cycle
paths/ lanes, pedestrian refuges, shuttle bus to CBD/school
Programme 4: State Highway severance reduction: signals, over-bridges, narrowing via
threshold type treatments, speed reductions (school zone or temporary)
Page 26
Programme 5: Local road alternatives: local travel more on local roads and fewer State Highway
intersections, kerbing, LI /LO (Left in/Left out), review priority intersection controls
Programme 6: land use developments: controls on State Highway accesses, manage timing of
urban growth areas, Lake Hood
Programme 7: Do max; combination of all above including 4 laning of the existing state highway
and the construction of a second bridge
All of these programmes were discussed in detail and assessed in terms of their ability to achieve
the ILM problem statements and benefits and also achieving outcomes on realistic terms
(timeliness and cost).
These are summarised in the table included at the end of this section.
9.3 Option discussion
Within each of the programmes identified there are a range of options that could be
implemented that could deliver on the outcomes. How these options can be packaged together
to complement each other, or how they need to be packaged due to particular network needs
and/or dependencies to provide the best outcome for the entire network is important to
understand.
Options not taken forward:
First of all some discussion is required on options discarded from this point and why.
Programme 1 (Do min): was rejected as it doesn’t address the problem statements nor meet
any benefit outcomes. It is also a reputational risk to all agencies and given the District growth
is strong and anticipated to continue, this approach is not acceptable.
Programme 3 (Provision of alternates to private vehicles): Tinwald is affected by a large
component of rural based traffic where it is simply not feasible that alternates (eg public
transport) can provide for the needs. In addition a sensitivity analysis was carried out on the
existing traffic model to determine if a nominal 10% reduction in school trips was achieved
would this make a significant difference to traffic delays and other issues. The analysis showed
insignificant effects.
This does not mean a school plan is not desirable – it should be actioned, but the impact on the
overall network performance will be very small. Other parts such as independent cycle facilities
are integrated in all other solutions/programmes anyway so overall this programme is
discontinued.
Programme 6 (Land Use developments): It is recognised that the time to make change from
controlling land use change would take significant years to have effect. In addition any RMA
application could permit a large development inconsistent with the District Plan anyway so this
programme is discarded as unrealistic and not able to provide short term response to a present
issue or meet the PBC target outcomes.
Programme 7 (Do max – new bridge, 4 lane highway): While this achieves many benefits
implementation this option is expensive and is considered a long-term option in responding
issues post 2026. For an investment with a 40 year return period this option would need to be
investigated fully at a later date.
Options to take forward in a complementary role:
Travel planning and school travel plans. While limited in its ability to result in major impact
on the wider Tinwald network, these do have an important role to play in optimising
investment and can also flush out other previously unforeseen issues, or suggestions to the
overall main programme. There are also benefits to students and their families.
Page 27
9.4 Assessment of options on Intersection Delay
To test the options for delay at key intersections a number of scenarios were modelled. The
following results are summarised below.
At SH1/Graham all options except signals are improvements with a roundabout being clearly
the best. Signals at Graham are a major dis-benefit for the 2016 model. At Wilkin all options are
improvements over the do-minimum, even the signals at Graham. Again the roundabout at
Graham offers the best option to LOS at Wilkin but only marginally over other options. At Carters,
none of the options offers any significant betterment over the do-min.
Not included in this report but noted for comparison, the previous 2009 PFR report7
on
intersection upgrades at SH1/Lagmhor Street concluded a level of service drop initially for this
intersection treatment option with signals, much as above for signals at Graham St.
The 2026 model analysis shows a clearer differentiation with the roundabout at Graham clearly
improving delay at Graham with other minor improvements in level of service at Wilkin and
Lagmhor. Signals at Graham do produce improvements but less than the roundabout and other
intersections do not benefit.
Modelling
The following tables have been derived from the 2014 analysis of the updated traffic model and
show the Level of Service for intersections through Tinwald for 2016 and 2026 modelled years
and the morning peak, business hours and evening peak periods.
The different options indicated are aligned with the programmes that were discussed at the
stakeholder workshops held in 2014 and largely represent safety, State Highway severance and
local road options. Refer to Table 1 in Section 7 for level of Service band widths.
As discussed in that section for simplicity only the four main intersections (by volume) are shown
here, the other 3 modelled (Johnstone Street, Hassel Street and Maronan Road) can be viewed in
full in the Opus Options assessment report. In general they follow similar trends to that shown
for the main intersections.
Intersection
2016 SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
AM IP PM AM IP PM AM IP PM AM IP PM
Do Minimum C B C C B C E C F E C F
Option 1: left slip lane &
RT merge at Wilkin
C B C C B C B A C D C F
Option 1a: Signals at
Graham
D D D C C D B A C D C F
Option 1b: Signalised
ped crossing between
Agnes and Graham
B A B C B C B A B D C F
Option 1c: Signalised
ped crossing between
Graham and Jane
B A B C B C B A C D C F
Option 1d: Roundabout
at Graham
A A A C B C B A B D C F
Table 3: 2016 Model and level of service changes for options at main SH1/Tinwald intersections
7 Opus for the Transport Agency
Page 28
Intersection
2026 SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
AM IP PM AM IP PM AM IP PM AM IP PM
Do Minimum F D F F D F F F F F F F
Option 1: left slip lane &
RT merge at Wilkin
F C F F C F F C F F F F
Option 1a: Signals at
Graham
C D C F D F F C F F E F
Option 1b: Signalised
ped crossing between
Agnes and Graham
F C F F C F F C F F F F
Option 1c: Signalised
ped crossing between
Graham and Jane
F C F F C F F C F F F F
Option 1d: Roundabout
at Graham
A A A F C E F C E F F F
Table 4: 2026 Model and level of service changes for options at main SH1/Tinwald intersections
Intersection
SH1/Graham SH1/Lagmhor SH1/Wilkin SH1/Carters
OPTION 3: 2nd
river
bridge with:
AM IP PM AM IP P
M
AM IP PM AM IP PM
Do min C A C D B D F D F F C F
Option 3a: Signals at
Graham
D D D D B D F D F F D F
Option 3b: Signalised
ped crossing between
Agnes and Graham
B A B C B C F D F F D F
Option 3c: Signalised
ped crossing between
Graham and Jane
B A B D B D F D F F D F
Option 3d8
: left slip lane
Lagmhor & RT merge at
Wilkin and change
priority of local roads
parallel to SH1
C B C D C D C B C F D F
Table 5: 2026 Model and level of service changes for option 3 at main SH1/Tinwald intersections
8 Combination of options 1 and 3
Page 29
9.5 Discussion on second bridge (2026) key results
After a second bridge, signals at Graham are a major dis-benefit. All other options provide
benefits showing that they do so regardless of the second bridge. The left slip lane at Lagmhor
Street and right turn at Wilkin Street provide the best benefit to delay.
9.6 Discussion
In Tinwald, comparatively small numbers of turning vehicles (when compared with the numbers
of through vehicles on SH1) are likely to experience increasing delays. As a result of long delays
to right turners, drivers often turn left from the side roads on the East side and then U-turn into
West-side streets to re-enter the State Highway from the west side. The model also predicts this
and other re-routing affects.
The second bridge option returns actual delay data for the do minimum on all main intersections
turning right onto SH1 in the order of 1100 seconds (18 minutes). The 2026 Option 3d reduces
this significantly for all right turns to give results between 20-60 seconds for various
intersections.
9.7 Constraints and Dependencies
A supermarket proposal in the vicinity of SH1/South Street, currently subject to a resource
consent application at the time of writing this PBC, has as part of its application a proposal for
the developer to install traffic signals at that intersection. The effect of these proposed signals
on Tinwald is not immediately clear but initial evidence suggests that the distance from the
South Street intersection to the beginning of Tinwald (i.e. the Carters Terrace area) is sufficiently
large to result in the signals having a negligible effect. Certainly the effect further south would
be lower.
The signals at South Street may advance in the 2015-16 year but have been modelled only in
the 2026 programme as part of the do minimum option. There is likely to be only some minor
re-allocation of how trips are generated from the development and more impact likely on the
immediate area of the north approach to the SH1 Bridge.
The second Ashburton River urban bridge designation has been granted in 2014. From Council
feedback it is unlikely that this will be open until 2026 at earliest, therefore the modelling of
alternatives and options (refer Option 3 of 2026) reflects this by testing with and without the
bridge in the 2026 networks.
9.8 Key stakeholder feedback on alternatives and options
Timings
The key stakeholder group was in general agreement that the main intersections at Grahams
and Lagmhor are the main perceived problem in the community and that these are required to
be addressed as a priority in terms of timings. Less well understood by the group initially were
the interactions of the other intersections and how and why they currently operate as they do
with motorists self-regulating by trying different access points onto the State Highway from the
East where they aren’t congested or delayed less.
Following the presentation of background and traffic analysis information the group rapidly
understood the reasoning behind the discarding of the programmes described above and the
focusing of developing solutions and options around the remaining.
Stakeholder views outlined in section 8 were also informed by and fed into the discussions
related to programme assessment and evaluation.
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Page 31
10 Programme Options Development and Assessment
The programme option development process used a series of workshops to first brainstorm
programme alternatives and subsequently considering how different programmes stack up
against the desired benefits and outcomes previously noted. A review was held to analyse the
alternative programmes against a background of benefit, dis-benefits, risk, likely cost and
timeliness.
10.1 Programme Development
From the previous section the following programmes remained and were taken forward for more
detailed evaluation:
Programme 2: Safety approach which might include central medians, (wire rope), parking
management, cycle separation (in berms), separate lanes, speed reduction, lighting etc
Programme 4: State Highway severance reduction: signals, over-bridges, narrowing via
threshold type treatments, speed reductions (school zone or temporary)
Programme 5: Local road alternatives: increased local road travel/ reduced State Highway local
travel through fewer State Highway intersections, kerbing, LI /LO (Left in/Left out), better local
road routes
As these programmes individually did not address effectively all the issues or problems, it was
recognised that a preferred programme would involve blending elements from different
programmes.
10.2 Process
In August 2014, Opus updated the Ashburton Transport model, which was then 8 years old and
reported the updating process in the report “Tinwald Deficiency Assessment”.
This report included the data collected for the update, and following the re-validation, reported
an initial deficiency analysis of the existing network under 2016 and 2026 traffic demands. This
allowed key information to be presented to the first PBC workshop for context and improved
decision making.
Seven key intersections along the corridor were videoed to provide turning traffic data for the
model update and also to provide a means for counting pedestrians and cyclists.
The seven intersections surveyed are shown in the following figure and listed here as:
SH1/Maronan Road
SH1/Hassal Street
SH1/Graham Street
SH1/Agnes Street /Lagmhor Road
SH1/ Manchester Street
SH1/Wilkin Street
SH1/Melcombe Street /Carters Terrace
Page 32
Figure 2: Location of 2014 intersection surveys
This process and data analysis then enabled the following high level conclusions to be made:
1 Agnes Street: not used for entering SH. Low numbers in from SH1 north only
2 Manchester St: Largely as for Agnes
3 Wilkin Street is close to total volume on Graham St
4 Graham Street is greater volume than Carters Tce
5 Carters seems to be avoided due to proximity of Melcombe with turning priority laws
giving Melcombe priority, and therefore Wilkin preferred at that northern end
6 Melcombe (West side) is greater volume than Lagmhor and about equal with Maronan
7 Maronan (at south end) is comparable volume to Melcombe and majority of traffic is to
and from North
8 Lagmhor Road is low percent high commercial vehicles (%HCV) compared to higher on
Graham Street (construction traffic at Lake Hood will be currently influencing this)
9 Graham Street: Right turn avoidance by 2026 and intersection would benefit being
controlled
10 LOS: by 2016 Wilkin Street becomes worst (very low LOS) and others near ; Carters
Terrace and Manchester Street are long delays
11 LOS: by 2026 all Tinwald intersections well into LOS F
Table 6: Summary of results of Deficiency Assessment Report
From this high level analysis a series of indicative treatments at various intersections were
developed to take forward. These were also aligned with the first workshop programmes ( i.e.
those numbered 2,4 and 5). Opus then carried out further modelling to give indicative responses
to a range of typical options being discussed in alternative programmes, and produced a report
immediately prior to the 2nd
PBC workshop titled “SH1 Draft Programme Options Assessment”.
N
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Example treatments are summarised as follows and typical generic examples are shown in this
section of a seagull and slip lane type treatments. Note that not all treatments can be
implemented together and are presented as examples related to the programme theme:
ID Programme 2: Safety ID Programme 4:
Reduce SH1
severance
ID Programme 5: Local road
alternatives
1 Graham & SH1:
Seagull treatment
with merge lanes
1 Narrow various
sections via
threshold type
treatments and
speed restrictions
1 Lagmhor: Left in and left out
merge lanes
2 Relocate Ped crossing
to Graham - Jane
block
2 as above and add full seagull
treatment for Lagmhor right
turn plus Agnes restrict to
left in and out only.
3 Wilkin Street & SH1:
Seagull type
treatment with merge
lanes
3 Lagmhor: as above but
Agnes remains open as is
4 Roundabout
Graham/SH1
4 Manchester: Left in / out
only
5 signals at Graham/
SH1
5 Johnstone: Left in / out only
6 Carters: Left in / Left out
only
7 Carters: Left in / Left out
only and full Seagull /merge
south treatment on SH1 for
Melcombe
8 Melcombe: No RT on to SH1,
Allow SH1 RT on to Carters
as is
9 Melcombe: No RT on to SH1,
No SH1 RT on to Carters
Table 7: Typical Treatments allocated to different programmes9
Discussion on possible treatments
A seagull type treatment allows traffic travelling through and past intersections to remain in a
through lane but also has the advantage of giving side road traffic a merge (acceleration lane)
to merge with them (view sketch example in the appendices).
Examples of this type of treatment can be seen at the Southern end of Temuka where
Southbound traffic from the old state highway (King Street) merges with SH1 South.
9 View Appendices for typical examples of these treatments
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A threshold treatment is typically designed to give the impression of a narrowing of the through
lane of the state highway which tends to reduce speeds and also gives a clear signal to motorists
that there is a change in the corridor (e.g from a rural speed environment to urban).
Examples locally are the entrance to Rakaia Township on SH1.
Other intersection treatments reviewed as options but discarded are signals and a roundabout
at Lagmhor (discarded as unlikely to be able to provide adequate stacking distance with the
railway crossing too close to the highway. Land take and business proximity also meant this
would be difficult to achieve).10
The Carters Terrace intersection was considered for major improvements, but the height
restricting railway over bridge on Melcombe street side would make this unusable for tall
vehicles.
10.3 Typical treatment example sketches
Figure 3: Seagull example and explanation
Figure 4: Seagull example with left turn slip/merge lane out (eg at Lagmhor)
10 Reference 2009 PFR Opus report to the Transport Agency
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10.4 Do-Minimum Option
The initial traffic modelling considered the likely base networks at two future years: 2016 and
2026. This was reported in the Opus “Draft Programme Options Assessment”, report.
The 2016 Do minimum network runs modelled the existing roads and highway as is. The 2026
model network is identical except for the signalised intersection at SH1/South Street included
on the basis that this is a current planning application that is most likely to proceed in that time
interval.
10.5 Programme Assessment
The table below highlights the key benefits and dis-benefits arising from the traffic modelling
analysis carried out and provides the evidence trail to understand the decision making process
to retain or reject the various parts of the programme recommended to be developed. Refer to
the Appendices for more in depth discussion on the assessment of the programmes developed.
Summary of Findings from Traffic Modelling of Indicative Programmes
1 Left turn acceleration lane at Lagmhor and right turn acceleration lane at Wilkin provide significant delay reductions for access on to SH1 and no impact on SH1 through traffic regardless of whether the Ashburton second river bridge is constructed. A change of priority at Wilkin/Grove to prioritise traffic from the South on Grove would provide benefit.
2 A roundabout at SH1/Graham would provide significant network wide benefits & reduced side road delay by 2026 (if no Ashburton river 2nd urban bridge), but does not improve pedestrian or cyclists safety issues. Some early small dis-benefits result from this sub-option.
3 Signals at SH1/Graham provide significant side road delay reductions by 2026 (if no Ashburton river 2nd urban bridge), but in 2016 all traffic re-routes to avoid them. Significant dis-benefit (delay) to the whole network due to traffic delays at signals. Does improve pedestrian and cyclists safety issues
4 Modal shift of school traffic does not provide significant reductions to delays overall
5 Signalised pedestrian crossings at either location proposed (of the two blocks between Jane and Lagmhor) do not provide significant reductions to side road delays but would provide safer crossings to pedestrians, cyclists, mobility scooters and children on scooters with corresponding dis-benefits to network performance.
6 Signals at South Street/SH1: The effect on the Tinwald network from any signals would be negligible due to the distance from this intersection over the North side of the bridge.
7 The 2nd bridge option removes a significant number of vehicles trying to access SH1 from local roads and does reduce SH1 volume as well, but by 2026 regardless of this reduction in volume there remain delays for all SH1 intersections side road traffic (albeit reduced from the do min/do nothing ie in the order of 15-60 seconds down from 1100 seconds)
8 The 2nd bridge creates significant economic benefits
9 Previous feasibility documents (for Agnes/Lagmhor signals) remain current with significant dis-benefit for signals at Lagmhor
10 Acceleration lanes, (Lagmhor and Wilkin) continue to provide benefit even if 2nd bridge option is carried out.
11 2016 model and specific comment on likely changes resulting from options: Option 1a( signals at Graham) ; Some traffic from Tinwald East would re-route to avoid signals and would require local road measures to constrain this, eg Agnes would become quicker due to signal operation at Graham providing gaps Option 1b and 1c: signalised crossings; both cause significant re-routing due to delays of crossings on the SH1 south of Lagmhor. West re-routes to Lagmhor and East via Grove. Option 1d: roundabout at Graham; causes significant re-routing to avoid roundabout in early years, again to Lagmhor and via Grove to avoid Graham
Page 36
12 Delays from signalised pedestrian crossings is not sensitive to the two locations tested therefore any improvement works should be sited from pedestrian desire line surveys rather than network performance.
Table 8: Summary of findings from Draft Programme Options Assessment Report
10.6 Cyclist and pedestrian specific comments
This business case and the options considered in the modelling have not included any
assessment of improvements to the cycling and pedestrian facilities ‘along’ the route.
Intersections and crossings have been but there is a clear need to consider the entire route and
wider still with how the local roads (footpaths or shared routes) feed into the state highway
section, and also how Ashburton via the bridge is better connected for pedestrians and cyclists.
Results from the model indicate that a signalised crossing between Agnes and Graham and
between Jane and Graham would provide significant improvements for walking and cycling.
Discussions with the stakeholders confirmed this.
10.7 Qualitative Assessment to deliver the benefits listed within the ILM
A subjective, qualitative assessment and workshop feedback indicate that a mix of all 3
programmes of local road alternatives with a safety and severance reduction programme has
the ability to deliver a higher proportion of the benefits sought in the ILM than options that
focus on one theme only. In reality any local road alternate has inherent safety outcomes and
all solutions have the ability to integrate State Highway severance reduction measures.
Summary of Assessment of Programmes against Benefits Statement
Using the rating table (Table 9) to
subjectively score the programmes
against the desired benefits is a valid
way of assessing them. Table 10
concludes that all programmes have
merits and overall similar performance
but when a focus is made on the %
weighting, that Programme 5 is the
best.
Table 9: Legend for rating of
programmes
Programme
Benefits 2: Safety 4: Severance
Reduction
5: Local road
alternatives
Understanding and support of
Projects by customers and
stakeholders (5%)
Timeliness and ability to deliver
programme (25%)
Efficiency and integrated (30%)
Improve accessibility of all users
(20%)
Improve safety (20%)
Total subjective assessed
benefit
7 6 8
Table 10: Subjective assessment of programmes vs benefits
Symbol Rating Description
Major
Positive
Produces major benefit
Minor
Positive
Produces minor benefit
- Neutral Produces no or negligible
benefit
x Dis-
benefit
Dis-benefit
FF Fatal Flaw Dis-benefit of oRoader
that should be
discontinued
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10.8 Discussion on the option results
In order to compare the example options as assessed in the modelling a multi-criteria analysis
has also been completed.
Options and sub-options were defined by first reviewing where the priority issues and problems
were and Option 1 (both merge lanes at Wilkin and Lagmhor) is easily identified as alleviating
access from west and East by low cost measures.
Option 2 (Tinwald school mode shift) was an attempt to understand if the model, and solutions,
were sensitive to the impact of a change that may be able to be achieved via a mode shift and if
it was practical and beneficial to target this area. Option 2 following these investigations was
discontinued as the model shows this had a negligible effect on the network.
Option 3 (the second river bridge) has been tested as a future solution (given confirmation of a
designation in 2014). This had to be modelled to understand any sensitivity related to this on
the network.
Each option has been assessed in terms of the following:
Main Options assessment
Option
Description
Side road
delay
impact
Ability to
reduce
network
travel
times
Improvement to
pedestrians/cyclists
1 Acceleration/merge
lanes
Significant
delay
reduction
for local
roads both
sides
Significant
reduction
for all
roads
both sides
Neutral -
2 Tinwald School
modal shift
Negligible - Negligible - Encouraged via better
facilities
-
3 Ashburton River 2nd
urban Bridge
(2026)
Transforms
network;
significant
delay
reductions
Significant
reductions
Minor desire lines impact
only
-
Table 11: Assessment of Main Options
Option 1 Sub-options assessment
Option
Description
Side road
delay
impact
Ability to reduce
network travel
times
Improvement to
pedestrians/cyclists
1a Signals at
Graham
Halves
worst right
turn delay
in AM peak
(2026)
Signals cause SH1
traffic delay which
reduces benefits
x Introduces controlled
crossing across and
SH1
1b Signalised
crossing
(Agnes
/Graham)
Negligible - Signals cause SH1
traffic delay which
reduces benefits
x Introduces controlled
crossing across SH1
1c Signalised
crossing
(Graham/Jane)
Negligible - Signals cause SH1
traffic delay which
reduces benefits
x Introduces controlled
crossing across SH1
1d Roundabout at
Graham
Halves
worst right
turn delay
in AM peak
(2026)
Provide additional
network benefit
to merge lanes
No improvement -
Page 38
Table 12: Assessment of Option 1 Sub-Options
Note for options 1a and 1d, a two tick rating would apply for delay if the second bridge didn’t
occur however this is reduced to one tick due to the predicted early years of disbenefit of these
options and the result of state highway traffic being delayed.
Option 3 Sub-options assessment
Option
Description
Side road
delay
impact
Ability to reduce
network travel
times
Improvement to
pedestrians/cyclists
3a Signals at
Graham
Negligible - Signals cause SH1
traffic delay which
reduces benefits of
merge lanes
x Introduces controlled
crossing across and
along SH1
3b Signalised
crossing north
Negligible - Signals cause SH1
traffic delay which
reduces benefits
x Introduces controlled
crossing across SH1
3c Signalised
crossing north
Negligible - Signals cause SH1
traffic delay which
reduces benefits
x Introduces controlled
crossing across SH1
3d Roundabout at
Graham
Minor Significant benefit
No improvement
/neutral
-
Table 13: Assessment of Option 3 Sub-Options
Discussion on Multi-Criteria Assessment and results
Results indicate that once a second bridge is constructed that the addition of signals or
signalised pedestrian crossing would have a negative impact on the network – however all merge
lanes continue to provide benefits.
Overall assessment, considering all impacts, benefits and dis-benefits across the network
indicates a roundabout at Grahams/SH1 is the most effective way to improve delays in the short-
medium term. This should be carried out in conjunction with merge lanes at Lagmhor (left) and
at Wilkin (right turn).
Signals are slightly less effective than the roundabout option.
Signalised pedestrian crossings do not provide any significant side road delay reductions but
would provide a safer crossing for pedestrians and cyclists. The model indicates location is not
sensitive for network performance for vehicles and if selected, they should be located to provide
best desire lines for these user groups. As noted, the working group gave a strong unified
message that the existing crossing between Lagmhor and Graham should be shifted South a
block due to safety concerns.
The key conclusions drawn from the above analysis are that while some areas of this network
aren’t performing well at peaks, most is operating acceptably. Nevertheless, it is notable that
within the next 10 years there is significant deterioration at all State Highway intersections along
the Tinwald corridor with problems and issues that developing. This therefore leads to a
conclusion that programme development should continue through the investigation phases, at
very least, so that any interventions can be introduced in a timely fashion.
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11 Recommended Programme
The recommended programme includes a number of parts that are most effective to network
efficiency if completed together but some degree of phasing and timing would be possible
without compromise.
The main core works include channelisation improvements at a number of key intersections that
will assist immediately with delay issues.
Concurrently a plan for investigating the delivery of a roundabout at Grahams should be
commenced.
Other supporting works packages including cycleway reviews, intersection priority reviews,
speed limit reviews and pedestrians crossing locations are all recommended to enhance the
entire network safety and efficiency.
11.1 Programme Overview
All three programmes have similar strategic responses and relatively very close benefits. Due to
the nature and type of the proposed works all have a mixture of safety, severance and local road
alternate type components. Many could support walkways and cycleways. The key to developing
this programme is understanding what part is core work now and what would best be developed
later.
Core Activities
The preferred programme of works recommended for delivery at or before 2026 includes all of
the core activities described below.
Core activities include channelisation improvements such as merge lanes (left turn at Lagmhor
and right turn merge lanes at Wilkin), as in every case they are proven to be beneficial to the
network regardless to what happens later with a second bridge or other intersection
improvements. They have no negative effect and are low cost. No private land is required and
the intended solutions have no major impact on the existing network (for example parking at
intersections and beside existing businesses is already restricted). Therefore acceptance is likely
to be very high and consultation and liaison requirements reasonably straight forward.
Due to the minor nature of these works it is envisaged that minor improvement funding is the
likely funding mechanism.
As part of the core work and in parallel with the above, an indicative business case should be
developed now to investigate a roundabout at Grahams/SH1.
Given the likely timeline for moving through the early phases it is important that this is
commenced now so that eventual construction can be timed for optimal opening, which may be
in the 2015-18 NLTP period.
Supporting Activities
The remaining intersection improvements at Carters/Melcombe, Manchester, Johnstone and
Agnes all fit in with the above core works as they assist with the desired outcomes of restricting
movement on the network and provide more channelisation to assist the whole network. South
of Graham the other (currently minor traffic volume) intersections would also benefit from a
local road review that would check any improvement strategy or changes that could be
accommodated to enhance the entire network.
Optional
If funding and opportunity value allows, crossing points should be established in conjunction
with the above intersection improvements, and at both blocks (Graham/Jane and
Graham/Agnes) so that pedestrians and cyclists have further safe opportunity to cross the state
highway.
Page 40
A cycle network plan should be developed that would consider and include the following key
points:
should the current cycleway be removed from the state highway on to dedicated new cycle
paths on the West side (in the existing green area), and on the East side incorporated into
a shared footpath?
A complete review of cycleway connectivity from the local roads, particularly on the West
side of the state highway and how this network feeds into the state highway and further
north around the current Ashburton River bridge.
A school travel plan should be completed.
A local roads’ intersection review should be undertaken of vehicle priorities focusing on how to
best support the other actions that come from this report and the likely programme of works
ahead.
A speed limit review carried out.
11.2 Programme Implementation Strategy and Trigger Points
The indicative programme11
implementation is composed of the following steps
Short term (2015-18 funding programme)
Conduct a single IBC for roundabout at Graham and short term works (Lagmhor Road
and Wilkin Street channelization) and other related supporting works
Develop plans for investigating the entire route (and feeder streets) for how cyclists and
pedestrians are best catered for
Medium term (2018-21 funding programme)
Construct cycleway improvements along and across state highway corridor
From short term investigations:
Other pedestrian crossings and thresholds
Other minor intersection improvements and modifications
Construct roundabout at Graham and other works required in local streets for any
priority changes
Speed limit review
Long term (2026 +)
When Ashburton river urban 2nd
bridge constructed; complete priority changes to local road
network
11
This is a first estimate of timing and funding and any programme is subject to funding criteria at the
time
Page 41
Note Implementation responsibilities will be determined as projects are developed
Page 42
12 Recommended Programme – Assessment
The preferred programme has been reviewed using the Transport Agency assessment
framework and given a funding profile of M/M/L
The programme has been derived from the issues and problem statements.
Project risks are assessed as low.
Low cost solutions have been tested for effectiveness and discontinued where low or nil
benefits found to exist.
This section assesses the performance of the recommended programme against three key
criteria:
Programme Outcomes
Programme Risks
Value for Money
12.1 Programme Outcomes
The programme has been specifically targeted and derived to meet all of the specific outcomes
from the issues and problem statements including:
provide an integrated approach to land use and transportation planning so as to
minimise the adverse effects of one on the other;
provide safe and efficient access to SH1 at Tinwald
Encourage and enable safe use of alternative modes such as walking and cycling.
Reduce side friction and conflict between through and local vehicles on State highway
arterials.
Page 43
12.2 Programme Risk
This section considers the risks associated with the programme. These can be broken down
into the following key risk areas with a brief commentary on reasons for the subjective
assessment scores: Table 14: Indicative Programme
Risk Assessment Commentary
Technical
Low Recommendations detail standard solutions
widely used in NZ
Operational
Low Standard details that cater and allow for all
operational risks
Financial
Low Known costs are likely to be on low side and
funded. Some discussion on where funding split
lies may have some minor impact on ADC. Can be
staged.
Stakeholder/Public
Low Low as high expectation for something to happen.
Even where works most likely to occur the impact
on directly affected businesses is negligible to
none. Some risk of expectations of signals or
more substantial solutions.
Environmental and
Social Responsibility
Low Low impact as only minor green space required.
Already urbanised area and proposals are only
modest changes.
Safety
Low All solutions are targeted to improve safety
Economy
Low All solutions are targeted to improve efficiency
and provide value for money.
Table 15: Risk Assessment
12.3 Value for Money
Certainty of the ability to achieve value for money arrives from a variety of ways. First is that the
traffic model has steered us to where we are likely to get best value by indicating when we need
to do what intervention. The proposed programme is able to address identified problems and
achieve benefits, whilst proposing low cost interventions. We have also tested sensitivity of some
solutions and recommended no action where these didn’t indicate a positive result. While no
actual project cost estimating exercise has been developed this early in the process we know
from anecdotal evidence that the costing parts of the programme recommended are reasonably
well understood from other projects of similar scale and complexity.
12.4 Assessment Profile
The programme was assessed using the latest Transport Agency Investment Assessment
Framework profiles. An assessment profile of M/M/L has been determined for the programme
using the Transport Agency’s funding allocation process as detailed below:
Strategic fit of the problem, issue or opportunity that is being addressed: M
This is based on the criteria being satisfied of:
Easing of congestion in main urban areas
Effectiveness of the proposed solution: M
This is based on all criteria being satisfied, including being part of a Transport Agency supported
strategy (Ashburton Transport Study); is significantly effective (as proven by the revised traffic
modelling carried out); provides a long term solution with enduring benefits (also proven by
traffic model)
Benefit-Cost efficiency of the proposed solution: L
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While no economic assessments have been formally carried out, from known project costs of
other similar type work packages, the benefits are known to be relatively good for modest
funding. Therefore a BCR between 1 and 2 is nominated as an interim measure until this can be
confirmed in subsequent phases.
13 Programme Financial Case
13.1 Indicative cost
No costing work has been completed at this stage. Options have only been considered in low,
medium or high cost likelihoods and scenarios. The proposed programme is likely to only be
either minor works or low cost block projects.
13.2 Funding arrangements
It is intended that these investments will be funded by a mixture of work categories and will be
split by organisation depending on the project. I.e. State Highway and local road contributions
in line with standard arrangements although ADC has indicated some funding for use on
Indicative Business Cases.
13.3 Affordability
The affordability of the overall programme is likely to be good given the relatively low cost of
implementing the works described in the core activities from indicative past projects of similar
nature. In addition no major land issues are foreseen and ground conditions are also relatively
good where any new construction is likely. Therefore project risks (and costs) are accordingly
rated low.
No major affordability issues are envisaged.
Page 45
PART C – DELIVERING & MONITORING THE PROGRAMME
14 Management Case
14.1 Programme Governance and Reporting
Governance Structure
The project’s governance structure involves the senior key members of The Transport Agency
Christchurch office and ADC that provide strategic leadership and who perform an oversight
role to ensure that all and any improvement works are well planned and aligned with other
investments in the area. The senior staff from both organisations have roles and responsibilities
that include:
Strategic Leadership
Ensure a clear and concise vision is in place
Approve the outcomes of the PBC and subsequent business cases
Ensure that the delivery team develops the project in a way that coordinates and
integrates well with the strategic direction of each organisation
Oversight (monitoring, evaluation and reporting)
Provide a discussion forum between ADC and the Transport Agency to respond to
requests for decisions or recommendations received from the delivery team
Review the impact of the programme
Monitor the efficiency (and coordination) of resource in each organisation to achieve
the outcomes sought in the business case
Ensure accuracy and timeliness of reporting processes and systems are maintained at
a high level at all times
(No Project Control Group, PCG, is thought necessary for this project due to the particular
requirements of this project being not complex enough to warrant it).
Project manager
Each organisation shall appoint a project manager responsible for delivering the project. The
project manager from the Transport Agency leads and manages the team on a day to day basis.
The programme is to be submitted to the LTP/NLTP and delivered as a series of related but
separate projects.
14.2 Stakeholder Engagement and Communications Plan
The stakeholder engagement approach is to continue as is with the key group being fully
incorporated into the process via specific workshops throughout. The second tier of
stakeholders will also be given specific ability to feed their input in at key points. They will also
receive all information available. Individual projects will expand on this as detailed development
occurs, and include general public consultation per normal project development.
14.3 Programme Performance and Review
The benefit map is included in the Appendices and this covers how investment KPI’s can be
measured simply and effectively. In addition now that we have a baseline survey, and good traffic
data, all subsequent monitoring and videos of intersections etc, can be used to check and
validate improvements post construction.
Crash rates can be monitored for any emerging new trends or improvements. Anecdotal
evidence from emergency services, via interviews and submission to public processes (such as
Page 46
LTP’s), will provide good feedback on how the corridor performance (and local roads) has
improved.
Page I
Appendix A - Investment Logic Map
Page III
Appendix B – Benefits Map
Page IV
Appendix C – Location Map
Page V
Appendix D – Background Evidence to Needs
Operating Environment
With the competing interests of long-distance travel, often of significant economic value, and
the transport demands of residential (and to a lesser extent commercial) growth in Tinwald,
there is the need to understand the key problems and issues on this corridor.
The strategic solution needs to be found that will best meet the expectations and objectives of
the strategic function of the State highway and the aspirations of, and developments aligned
with, the Ashburton Futures Strategy.
Growth in population and employment
The population of Ashburton District was estimated to be 30,100, as at 30 June 2011 and the
recent 2013 census data returns an actual of 31,000. Over the previous census period to 2006,
the population of Ashburton District increased 7.6%, making Ashburton District one of the
fastest growing rural districts in the country at the time12
. This is much higher growth than the
previous census period, (1996– 2001), when the district’s population grew by just 1.1%.
The district’s population has grown steadily over the past few years, driven primarily by local
economic growth. Ashburton District’s population looks set to continue this growth, reversing
earlier trends of low or no growth. The 2013 census data shows a further large 13 % increase
from 2006 to 2013.
The demographics of Ashburton District are changing, and they are expected to change further
in the future. Notable in the latest census data is the large increase in the 25-44 age range
synonymous with the likely increase in dairy activity and some general population shift from
Christchurch post-earthquakes. Population medium projections13 estimate that in 2016
Ashburton District’s population will have increased to 31,200, and a medium projection estimate
indicates a population at 2031 of 33,900 people (and a high projection estimate for 2031 of
37,000).
Within Ashburton, Tinwald as a sub-area represents about 18% of the Ashburton population14.
Tinwald also has a notable light industrial zone towards its southern end. The Future Ashburton
Development Plan recommended that some further residential (at usual suburban densities and
lower greenbelt densities) development is allowed to provide choice in living environment to the
east and west of the current Tinwald urban area. Some further investigation of the commercial
area is proposed to address the lack of focal meeting space for the area, the mix of activities,
its size and the strip nature of commercial development which is occurring there.
The growth in population (and employment in the Tinwald commercial and industrial areas) and
developing land use patterns will put increasing pressure on the transport network through the
area, particularly SH1 which forms the backbone to the road network and is the only nearby
route to cross the Ashburton River into Ashburton CBD area.
Traffic Movements through Tinwald
In 2013, the AADT on State highway 1 in Tinwald was 22,327, with 12.94% of the traffic stream
being trucks (higher than normal for urban arterials). State highway traffic volumes are
increasing at approximately 1.8% / year.
Independent surveys taken in 2012 show that State Highway traffic travelling straight through
Ashburton/Tinwald constitute about 12-14% depending upon time of day. Therefore the balance
of traffic on the state highway in Tinwald has at least one end of their journey located within the
Ashburton township.
12 Ashburton population facts and figures report, Sept 2011, ADC Community Planning Department 13
NZ Stats: Area unit population projections by Territorial Authority ( 2013 Data)
14
Source : ADC Community Planning Department
Page VI
The high State highway volumes and speed of trucks make pedestrian crossing of the State
Highway difficult, especially for school children.
Safety
Road user safety on SH1 through Tinwald is perceived as one of the key transport issues by the
local community. This is principally focussed on right turn movements from side roads onto
the State highway throughout Tinwald. The other safety issue relates to crossing the State
highway by pedestrians and cyclists.
Over the 5 years of crash records (2009-13) there have been 41 crashes between the Ashburton
River and the southern urban boundary with 18 at intersections. This section of state highway
is approximately 3 km long with 9 T-intersections and 2 cross-road intersections.
There has been one fatal crash, (of a van failing to give way to a pedestrian near Graham Street),
3 resulting in serious injuries and 10 resulting in minor injuries. The crashes are evenly spread
along all intersections. This recorded crash rate is lower than the typical crash rates as outlined
in the Economic Evaluation Manual.
Delay
Most key intersections along the Tinwald corridor experience increasing delays at peak periods
during the day. The level of service for vehicles turning right onto SH1 by 2016 is considered to
be moderately high with predictions that by 2026 it will increase significantly to be a very poor
level of service.
Status of the Evidence Base
Previous studies have occurred in 2008 (Ashburton Transport Study) and 2009 (PFR: SH1: Agnes
St/Lagmhor Road intersection Signalised Upgrade – Tinwald). These provide significant levels
of transport related data and information. Updated crash and traffic volume data has been
sourced from the Transport Agency systems to 2013.
Video analysis was carried out in mid-2014 of 7 SH1 intersections including pedestrian and
cyclist counts.
Whilst there are acknowledged growth proposals for east and west Tinwald, the actual level and
rate of development is unknown. Assumptions are incorporated within the transport model
(recently updated) as used in the analysis underpinning the Ashburton Transport Study
Geographical and Environmental Background Information
The population of Ashburton District increased 7.6% over the census period to 2006 and a
further 13% for the period 2006 to 2013 making this one of the fastest growing Districts in the
country at the time. The urban area covers approximately 230 hectares and is predominately
residential, although there are significant areas of industrial development at the southern end.
Facilities include a primary school (roll of 230), and other schools in Ashburton over the nearby
bridge who rely on the catchment of Tinwald (ie students travel through to Ashburton), a pre-
school, a retirement home, several churches, golf course, velodrome and sports centre, and a
museum.
Land is generally flat being situated on the Canterbury Plains, with the braided Ashburton river
bordering Tinwald to the northeast.
Page VII
Social and Community Background Information
Tinwald residents have a lower average income than the rest of Canterbury, with a median
income of $22,400 compared to the Canterbury regional median income of $23,500. A
comparatively high proportion of Tinwald’s workforce is employed as labourers, machinery
operators and drivers, and a comparatively low proportion are employed as managers and
professionals. 39% of Tinwald residents do not have school level (or higher) qualifications,
compared to 25% in the Canterbury region. Tinwald Primary School has been rated as Decile 6
by the Ministry of Education.
Tinwald has a high proportion of older people, with 17% over 65, compared to 14% in the
Canterbury region (2006 data). However there is a noticeable increase in the 25-55 age group
that is starting to change trends not yet picked up in all census trend graphs.
Page VIII
Appendix E – Background information to development of
options
Assessment of Option - Programme 2: Safety
Description: This programme option focuses on improving safety along the corridor by
reviewing key intersections and suggesting treatments that either reduce risk or are specific
safety improvement treatments, particularly for vehicles.
Programme 2/1: Seagull type (ie half seagull) treatment at SH1/Graham. This addresses
the traffic originating from the East trying to turn right on to SH1 by incorporating a north
bound merge lane and a left in slip lane from SH1.
How it delivers against the outcomes: This treatment would make the right turn
significantly easier therefore efficiency and safety improves for motorists. Dis-benefits are
that the state highway severance would be slightly increased with no improvement to
pedestrian or cyclist safety. Losing parking on the West side of the highway may occur in
this location and could be argued as improving safety (outcomes).
Risks: Should be combined with other intersections treatments otherwise risk of only
shifting the safety risk at this intersection to others not improved. Loss of parking will have
some minor impact on the freedom of locals and public perception. The removal of some
trees and loss of green space is likely which will result in possibly some adverse public
comment and Council will have some comment on the loss of land (as some potentially
required for stormwater retention in this area).
Programme 2/2: On demand signalised pedestrian crossing – in Graham /Jane block or
Agnes /Graham block. Signalised crossings would provide a gap in state highway traffic
that would provide gaps for all other side-road traffic close by and combined with a median
island refuge would provide a safer crossing point for pedestrians.
How it delivers against the outcomes: The model analysis shows that delays on
intersections are not improved significantly (in both 2016 and 2026) but they would provide
additional safety to pedestrians with some minor corresponding dis-benefits to the overall
network as State Highway traffic is delayed a minor amount and side road traffic re-routes
to avoid these points of delay.
Risks: Pedestrian crossings mid-block could be an out-of-context surprise to state highway
traffic without other mitigation such as signage, thresholds and education. Could give a
false sense of security to users.
Programme 2/3: Seagull type treatment (ie half seagull) at SH1/Wilkin St. This addresses
the traffic originating from the East trying to turn right on to SH1 by incorporating a north
bound merge lane and a left in slip lane from SH1.
How it delivers against the outcomes: Similar to programme 2/1 this treatment would
make the right turn significantly easier therefore efficiency and safety improves for
motorists. Dis-benefits are that the state highway severance would be increased with no
improvement to pedestrian or cyclist safety. Some land most likely required ie the green
space to the West, which has been noted by ADC as potentially required for stormwater
disposal. Some parking areas on the West side in the vicinity of the pre-school would be
lost, or the entire road corridor could be moved even further West (ie further into current
green space) to retain them if the safe operation of the parking is achievable. Losing parking
on the West side of the highway in this location could be argued as improving safety.
Would be best combined with restricting traffic at Carters (refer other programmes) as this
would then direct traffic where it is best managed.
Risks: Should be combined with other intersections treatments otherwise risk of only
shifting the problem. Loss of parking will have some minor impact on the freedom of locals
and public perception. The removal of some trees and loss of green space is likely which
will result in some Council and possibly public risk.
Page IX
Programme 2/4: Roundabout treatment at SH1/Graham St. This addresses the traffic
originating from the East trying to turn right on to SH1 by constructing a roundabout on
SH1.
How it delivers against the outcomes: This treatment would significantly reduce side road
delay in 2026 but in 2016 local traffic re-routes to avoid this intersection (less than signals
option below). Dis-benefits are that the state highway severance would be marginally
increased with no improvement to pedestrian or cyclist safety.
Would be best combined with other intersections (refer other programmes) as this would
then direct traffic where it is best managed.
Risks: Programme timing and funding are major risks
Programme 2/5: Signals treatment at SH1/Graham St. This addresses the traffic originating
from the East trying to turn right on to SH1 by constructing signals on SH1.
How it delivers against the outcomes: This treatment would significantly reduce side road
delay in 2026 but in 2016 local traffic re-routes to avoid this intersection (more than
roundabout option). Benefits are that the state highway severance would be decreased with
improvement to pedestrian and cyclist safety. Dis-benefits are that the state highway delays
would be increased and corresponding loss of service.
Would be best combined with other intersections (refer other programmes) as this would
then direct traffic where it is best managed.
Risks: Programme timing and finding are major risks
Assessment of Option - Programme 4: Reduce State Highway Severance
Description: This programme option focuses on reducing the State Highway severance through
narrowing (standard threshold treatments), speed reduction, installing refuges for pedestrians
or a combination of all these at locations to be determined. Other options of over-bridges and
underpasses were also discussed and while not discounted at this stage they are thought to be
not economically justifiable, not a safe environment (underpass) and difficult to install in a
confined corridor. Other options of controlled (i.e. signalised) crossings of SH1 are discussed
above.
Programme 4/1: threshold type treatment at locations to be determined. This addresses
the traffic arriving at the end of the corridor so that a changed speed environment is
recognised from rural to urban or placed periodically along to reinforce environment or
key points
How it delivers against the outcomes: This treatment would make the crossing of the
state highway significantly better by providing refuges in the median area and shorter
distances across lanes. As a consequence of this programme the speed environment would
be less therefore safety benefits are also achieved. Safety is further enhanced by integrating
into this type of treatment by the usage of low cost signs that either restricts speed e.g.
school zones or variable message signs with ‘slow down” message.
Risks: Efficiency of the state highway could be compromised but all design would be in
accordance with standard widths for over-dimension and swept path tracking into side
roads.
Programme 4/2: speed management
Part time or permanent changes to speed – either school times/routes or modify 70 kph zone
etc.
Assessment of Option - Programme 5: Local road alternatives
Description: This programme option focuses on improving efficiency along the State Highway
corridor by reviewing key intersections and suggesting treatments that either removes delays
Page X
or direct traffic to where it is best managed through other treatments. It also encourages local
traffic to use local roads more and reduce State Highway volumes and access delays. Therefore
some dependencies occur and some specific safety improvements result directly from the
efficiencies as well.
Programme 5/1: Lagmhor street/SH1left out merge lane with full seagull intersection
treatment. This addresses the traffic originating from the West trying to turn left on to
SH1 by constructing a dedicated left merge and acceleration lane and a right turn
merge/acceleration lane from Lagmhor acceleration lane Southbound. Agnes traffic sub
options within this.
How it delivers against the outcomes: This treatment would improve network efficiency.
The left turn from the West on to the state highway is significantly easier by providing a
means to accelerate and merge with traffic and not wait. Right turning vehicles at Lagmhor
would also have an acceleration lane southbound. Variations to be considered include
keeping Agnes as is with full turning (self regulates as at peak this manoeuvre is already
difficult, or close Agnes right turn out. Safety and efficiency is increased and delays
improved.
Risks: Business risk at Agnes due to Pub and Shell service station access and will need to
be managed in consultation process. Design risk from large vehicle stacking over the rail
crossing (no different to current) but may compromise the projects ability to achieve
outcomes if space not there. Green space will be lost which has public risk.
Programme 5/2: Lagmhor street/SH1left out merge lane. This addresses the traffic
originating from the West trying to turn left on to SH1 by constructing a dedicated left
merge and acceleration lane only.
How it delivers against the outcomes: This treatment would improve network efficiency.
The left turn from the West on to the state highway is significantly better by providing a
means to accelerate and merge and it removes the current situation where a right turning
vehicle at Lagmhor can easily block all traffic waiting to turn left. So this also has a secondary
safety outcome.
Risks: Design consideration required to check large vehicle stacking over the rail crossing
(no different to current) where a dedicated left lane installed. Some parking most likely lost
on the area to North of Lagmhor but this would most likely improve safety. Businesses need
to be managed in consultation process. Some green space will be lost.
Programme 5/3: Manchester Street and Johnstone street: SH1 left in/left out only. This
directs the traffic originating from the East trying to turn right on to SH1 to other
intersections where it is best managed.
How it delivers against the outcomes: This treatment would improve network efficiency
by directing traffic mostly to either of Wilkin or Graham where other works are completed
to improve those intersections. Safety improved for all users as refuges can be installed as
part of blocking state highway access at this location. Already it is noticeable in the traffic
data that users are effectively self-monitoring this anyway but this formally completes it and
removes all risky right turn manoeuvres at peak times.
Risks: Dependant on other intersection improvements being completed first or in concert.
Programme 5/4: Carters Terrace/SH1left in/left out only. This directs the traffic
originating from the East trying to turn right on to SH1 to other intersections where it is
best managed.
How it delivers against the outcomes: This treatment would improve network efficiency
by directing traffic to Wilkin where other works are completed to improve this intersection.
Safety improved for all users as refuges can be installed as part of blocking state highway
access at this location. Already it is noticeable in the traffic data that users are effectively
self-monitoring this anyway but this formally completes it and removes all risky right turn
manoeuvres at peak times. A full closure of Carters at SH1 is a variant to this.
Risks: Dependant on other intersection improvements being completed first
Page XI
Programme 5/5: Carters Terrace/SH1left in/left out only and full seagull intersection
treatment at Melcombe Street. This addresses the traffic originating from the West trying
to turn right on to SH1 by constructing a right turn out acceleration lane southbound at
Melcombe.
How it delivers against the outcomes: This treatment would improve network efficiency
and safety and achieves all benefit outcomes. As for the above option 5/4, restricting
Carters Terrace or closing altogether are sub-options to investigate and would also improve
safety and efficiency.
(Note for subsequent phases that from the workshops carried out so far that the Police noted
that while the right turn south out of Melcombe is not used by many that this is the only right
turn south able to be made until over the bridge (from the West of Tinwald). Therefore keeping
this is as the status quo is perhaps of a higher importance to maintain than normal (not only
for emergency services), in terms of maintaining accessibility and effective local systems).
Risks: Dependant on other intersection improvements being completed first
Further notes on this programme: A dedicated left merge and acceleration lane for left turn
north out of Melcombe is not thought possible due to the proximity of the bridge and not
enough length to develop a merge. In addition the cycle lane on the state highway is most likely
to be relocated into the green space on the left side and will then need improvement works to
connect in a better way to the existing bridge cycle lanes (both sides). Refer other sections on
cycle lanes in general.
Page XII
Appendix F – Possible Treatments Discussion
Page XIII
Appendix G – 2016 and 2026 Level of service and actual volumes
AM vol AM delay LOS Total delay IP vol IP delay LOS Total delay PM vol PM delay LOS Total delay
Maronan L 95 5 A 475 70 5 A 350 127 5 A 635
R 3 9 A 27 4 9 A 36 5 11 B 55
Hassal L 2 5 A 10 4 5 A 20 2 6 A 12
R 31 11 B 341 43 10 A 430 38 14 B 532
Graham L 9 5 A 45 2 5 A 10 7 7 A 49
R 77 13 B 1001 69 12 B 828 86 20 C 1720
Agnes/Lagmhor Agnes L 0 6 A 0 0 6 A 0 1 8 A 8
T 0 14 B 0 0 13 B 0 0 23 C 0
R 0 15 B 0 0 14 B 0 0 24 C 0
Lagmhor L 117 7 A 819 108 7 A 756 92 8 A 736
T 2 16 C 32 0 15 B 0 0 25 C 0
R 5 14 B 70 2 13 B 26 4 23 C 92
Manchester L 2 7 A 14 1 7 A 7 2 11 B 22
R 49 21 C 1029 0 16 C 0 43 38 E 1634
Wilkin L 2 7 A 14 0 7 A 0 0 11 B 0
R 114 37 E 4218 85 24 C 2040 63 51 F 3213
Carters/Melcombe Carters L 0 7 A 0 0 7 A 0 0 14 B 0
T 0 24 C 0 0 20 C 0 0 46 E 0
R 36 32 D 1152 21 23 C 483 17 56 F 952
Melcombe L 154 15 B 2310 58 9 A 522 81 11 B 891
T 0 20 C 0 0 23 C 0 0 58 F 0
R 0 24 C 0 0 20 C 0 0 46 E 0
Total side
road traffic 698
Total side
road delay 11557
Total side
road traffic 467
Total side
road delay 5508
Total side
road traffic 568
Total side
road delay 10551
(mins) 192.6 (mins) 91.8 (mins) 175.9
2016 Results
Page XIV
AM vol AM delay LOS Total delay IP vol IP delay LOS Total delay PM vol PM delay LOS Total delay
Maronan L 356 512 F 182272 74 6 A 444 33 9 A 297
R 5 512 F 2560 5 14 B 70 8 17 C 136
Hassal L 18 11 B 198 4 6 A 24 2 8 A 16
R 62 820 F 50840 45 16 C 720 119 68 F 8092
Graham L 219 14 B 10 6 A 60 10 8 A 80
R 70 1090 F 129 30 D 3870 107 238 F 25466
Agnes/Lagmhor Agnes L 0 318 F 0 0 8 A 0 0 86 F 0
T 43 318 F 13674 2 25 C 50 68 105 F 7140
R 40 1090 F 43600 31 32 D 992 104 253 F 26312
Lagmhor L 157 387 F 60759 115 11 B 1265 65 34 D 2210
T 1 389 F 389 1 26 D 26 39 41 E 1599
R 7 93 F 651 4 26 D 104 6 61 F 366
Manchester L 132 16 B 2112 2 9 A 18 28 20 C 560
R 31 1021 F 31651 38 46 E 1748 102 263 F 26826
Wilkin L 11 11 B 121 0 9 A 0 1 16 C 16
R 31 1109 F 34379 56 62 F 3472 104 300 F 31200
Carters/Melcombe Carters L 0 27 D 0 0 10 A 0 0 23 C 0
T 6 131 F 786 0 43 E 0 0 117 F 0
R 30 1114 F 33420 32 62 F 1984 101 269 F 27169
Melcombe L 71 957 F 67947 67 17 C 1139 101 127 F 12827
T 0 958 F 0 0 54 F 0 101 127 F 12827
R 13 155 F 2015 0 44 E 0 0 117 F 0
Total side
road traffic 1303
Total side
road delay 527374
Total side
road traffic 615
Total side
road delay 15986
Total side
road traffic 1099
Total side
road delay 183139
(mins) 8789.6 Ratio est. #REF! (mins) 266.4 Ratio est. #REF! (mins) 3052.3
2026 Results