Integrated Transport Assessment State Highway 1 Johns …resources.ccc.govt.nz/files/projectinfo/1355101618.RFIAttachmentB... · Integrated Transport Assessment State Highway 1 Johns

Integrated Transport Assessment

State Highway 1 – Johns Road (The Groynes to Sawyers Arms Road)

Prepared for NZ Transport Agency

April 2013

SH1 Johns Road (The Groynes to Sawyers Arms Road) Integrated Transport Assessment

Status: Final April 2013 Project number: Z1818001 Our ref: Johns ITA revC FINAL.docx

Executive Summary This Integrated Transport Assessment (ITA) provides a full appraisal of the multi-modal transportation effects of the proposed State Highway 1 – Johns Road: The Groynes to Sawyers Arms Road improvement project. The improvements proposed along this 4km section of State Highway are part of the Western Corridor improvements, which in turn form part of the Christchurch Motorways suite of projects being undertaken by the NZ Transport Agency within the Roads of National Significance programme. The Groynes to Sawyers Arms Road (G2S) upgrade includes 4-laning the entire project length, including the provision of central median and wire rope barrier, improved road cross section, wide sealed shoulders and improved street lighting and stormwater management. This ITA considers the safety and operational impacts of the proposals. The CAST transportation model is used to assess the likely impact of the proposals including comparison with the do-minimum approach. The 2006 and 2011 base years are used and compared against the 2026 and 2041 horizon years. The modelling demonstrates that, operationally, there are significant positive effects in upgrading G2S as opposed to continuing with the current arrangement along this section of the corridor. A number of turning movements are prevented as part of the G2S project – however, interestingly, it is demonstrated that without G2S upgrade the local road network in the vicinity of the G2S project length would suffer significant negative effects. This is because G2S upgrade is critical to the efficient operation of SH1, as well as the wider road network, and without upgrading this section there would be considerable congestion which would likely result in traffic diverting to inappropriate local roads. The proposed project will assist in improving the operation and Level of Service of State Highway 1 and consequently the movement of people and freight, thereby supporting the key government objectives to improve productivity and economic growth (as well as improving access to a key tourism gateway). The ITA also considers sustainable modes and it is established that the proposals contained within the G2S project will provide some improvements for pedestrians and cyclists. It is therefore concluded that the G2S project is a critical element of the infrastructure improvements being proposed in this locality and will bring about benefits that support the wider national and regional goals for transport.


Status: Final April 2013 Project No.: Z1818001 Our ref: Johns ITA revC FINAL.docx

NZ Transport Agency

Johns Road G2S Integrated Transport Assessment

CONTENTS

Executive Summary ......................................................................................................................... i

1 Introduction .............................................................................................................................. 1

1.1 Background ......................................................................................................................... 1

1.2 Project Description ............................................................................................................... 1

1.2.1 Christchurch Western Corridor........................................................................................ 1

1.2.2 The Groynes to Sawyers Arms Road Four Laning ............................................................ 1

1.3 National Context .................................................................................................................. 2

2 Planning & Funding Context ...................................................................................................... 3

2.1 National Framework ............................................................................................................. 3

2.1.1 Government Policy Statement 2012 ................................................................................ 3

2.1.2 National Land Transport Programme 2012-2015 .............................................................. 3

2.1.3 State Highway Asset Management Plan 2012-15 ............................................................. 3

2.2 Local Framework ................................................................................................................. 3

2.2.1 Canterbury Regional Land Transport Strategy 2012-2042 ................................................. 3

2.2.2 Greater Christchurch Transport Statement (GCTS) .......................................................... 4

2.2.3 Christchurch Transport Strategic Plan (CTSP) 2012-2042 ................................................ 4

3 Existing Situation...................................................................................................................... 4

3.1 Network Description ............................................................................................................. 4

3.2 Existing Network Issues ....................................................................................................... 6

3.3 Non-Car Modes ................................................................................................................... 6

3.3.1 Public Transport ............................................................................................................ 6

3.3.2 Walking & Cycling .......................................................................................................... 6

3.4 Safety Analysis .................................................................................................................... 6

3.4.1 State Highway 1 ............................................................................................................ 6

3.4.2 Local Road Network....................................................................................................... 8

4 Future Scenario ....................................................................................................................... 9

4.1 Assessment Years ............................................................................................................... 9

4.2 Model Output Data ............................................................................................................... 9

5 Assessment of Traffic Impacts ................................................................................................... 9

5.1 Base Year 2006 ................................................................................................................... 9

5.2 2011 Post Earthquake Traffic .............................................................................................. 10

5.2.1 Intersection LoS .......................................................................................................... 10

5.2.2 Link Delay ................................................................................................................... 12

5.2.3 Link Saturation ............................................................................................................ 12



5.3 2026 Design Year .............................................................................................................. 13

5.3.1 2026 Intersection LoS AM Period .................................................................................. 13

5.3.1.1 Johns Road / Sawyers Arms Roundabout ............................................................... 14

5.3.1.2 Johns Road / Wilkinsons Road Intersection ............................................................ 15

5.3.1.3 Johns Road / Greywacke Road Intersection ........................................................... 15

5.3.1.4 Johns Road / Gardiners Road Intersection ............................................................. 16

5.3.1.5 Johns Road / Clearwater Roundabout .................................................................... 17

5.3.1.6 Gardiners Road / Wilkinsons Road Intersection ...................................................... 18

5.3.1.7 Gardiners Road / Hussey Road Intersection ........................................................... 18

5.3.1.8 Gardiners Road / Sawyers Arms Road Intersection ................................................. 18

5.3.2 Link Flows 2026 AM Peak ............................................................................................ 19

5.3.3 2026 Intersection LoS PM Period .................................................................................. 19

5.3.3.1 Johns Road / Sawyers Arms Roundabout Intersection............................................. 20




5.3.3.5 Johns Road / Clearwater Intersection ..................................................................... 22




5.3.4 Link Flows 2026 PM Peak ............................................................................................ 24

5.3.5 2026 Summary ............................................................................................................ 25

5.4 2041 Design Year .............................................................................................................. 26

5.4.1 2041 Intersection LoS AM Period .................................................................................. 26

5.4.1.1 Johns Road / Sawyers Arms Road Roundabout ...................................................... 26




5.4.1.5 Johns Road / Clearwater Avenue Intersection ......................................................... 29




5.4.2 Link Flows 2041 AM Peak ............................................................................................ 30

5.4.3 2041 Intersection LoS PM Period .................................................................................. 31

5.4.3.1 Johns Road / Sawyers Arms Road Intersection ....................................................... 31




5.4.3.5 Johns Road / Clearwater Avenue Intersection ......................................................... 34






5.4.4 Link Flows 2041 PM Peak ............................................................................................ 35

5.4.5 Overall Intersection LoS 2041 PM Peak ........................................................................ 37

5.4.6 2041 Summary ............................................................................................................ 38

6 Evaluation & Discussion.......................................................................................................... 38

6.1 Network Impact.................................................................................................................. 38

6.2 Safety Evaluation ............................................................................................................... 38

6.3 Non-Motorised Road Users ................................................................................................ 39

7 Conclusion ............................................................................................................................. 39

LIST OF TABLES

Table 3-1: Severity of Crashes ....................................................................................................... 6

Table 3-2: Annual Distribution of Crashes ....................................................................................... 7

Table 3-3: Crash Causation Factors of Reported Injury Crashes ....................................................... 7

Table 3-4: Environmental Factors ................................................................................................... 7

Table 5-1: 2011 LoS State Highway Network ................................................................................. 11

Table 5-2: 2011 LoS Local Network .............................................................................................. 12

Table 5-3: 2026 Without G2S Johns Road / Sawyers Arms Roundabout .......................................... 14

Table 5-4: 2026 With G2S Johns Road / Sawyers Arms Roundabout .............................................. 14

Table 5-5: 2026 Without G2S Johns Road / Wilkinsons Road Intersection ....................................... 15

Table 5-6: 2026 With G2S Johns Road / Wilkinsons Road Intersection ............................................ 15

Table 5-7: 2026 Without G2S Johns Road / Greywacke Road Intersection....................................... 15

Table 5-8: 2026 With G2S Johns Road / Greywacke Road Intersection ........................................... 16

Table 5-9: 2026 Without G2S Johns Road / Gardiners Road Intersection ........................................ 16

Table 5-10: 2026 With G2S Johns Road / Gardiners Road Intersection ........................................... 16

Table 5-11: 2026 Without G2S Johns Road / Clearwater Roundabout ............................................. 17

Table 5-12: 2026 With G2S Johns Road / Clearwater Roundabout .................................................. 17

Table 5-13: 2026 Without G2S Gardiners Road / Sawyers Arms Road Intersection .......................... 18

Table 5-14: 2026 With G2S Gardiners Road / Sawyers Arms Road Intersection ............................... 18

Table 5-15: 2026 Without G2S Johns Road / Sawyers Arms Roundabout Intersection ...................... 20

Table 5-16: 2026 With G2S Johns Road / Sawyers Arms Roundabout Intersection .......................... 20

Table 5-17: 2026 Without G2S Johns Road / Wilkinsons Road Intersection ..................................... 20

Table 5-18: 2026 With G2S Johns Road / Wilkinsons Road Intersection .......................................... 21

Table 5-19: 2026 Without G2S Johns Road / Greywacke Road Intersection ..................................... 21

Table 5-20: 2026 With G2S Johns Road / Greywacke Road Intersection ......................................... 21

Table 5-21: 2026 Without G2S Johns Road / Gardiners Road Intersection ....................................... 22


Table 5-23: 2026 Without G2S Johns Road / Clearwater Intersection .............................................. 22



Table 5-24: 2026 With G2S Johns Road / Clearwater Intersection................................................... 23



Table 5-27: 2041 Without G2S Johns Road / Sawyers Arms Road Roundabout ............................... 26

Table 5-28: 2041 With G2S Johns Road / Sawyers Arms Road Roundabout .................................... 26

Table 5-29: 2041 Without G2S Johns Road / Greywacke Road Intersection ..................................... 27

Table 5-30: 2041 With G2S Johns Road / Greywacke Road Intersection ......................................... 27

Table 5-31: 2041 Without G2S Johns Road / Wilkinsons Road Intersection ..................................... 27

Table 5-32: 2041 With G2S Johns Road / Wilkinsons Road Intersection .......................................... 28

Table 5-33: 2041 Without G2S Johns Road / Gardiners Road Intersection ....................................... 28


Table 5-35: 2041 Without G2S Johns Road / Clearwater Avenue Intersection .................................. 29

Table 5-36: 2041 With G2S Johns Road / Clearwater Avenue Intersection ...................................... 29



Table 5-39: 2041 PM Without G2S Johns Road / Sawyers Arms Road Intersection .......................... 31

Table 5-40: 2041 PM With G2S Johns Road / Sawyers Arms Road Intersection ............................... 32

Table 5-41: 2041 PM Without G2S Johns Road / Wilkinsons Road Intersection ............................... 32

Table 5-42: 2041 PM With G2S Johns Road / Wilkinsons Road Intersection .................................... 32

Table 5-43: 2041 PM Without G2S Johns Road / Greywacke Road Intersection ............................... 33

Table 5-44: 2041 PM With G2S Johns Road / Greywacke Road Intersection ................................... 33

Table 5-45: 2041 PM Without G2S Johns Road / Gardiners Road Intersection ................................. 33

Table 5-46: 2041 PM With G2S Johns Road / Gardiners Road Intersection ..................................... 34

Table 5-47: 2041 PM Without G2S Johns Road / Clearwater Avenue Intersection ............................ 34

Table 5-48: 2041 PM With G2S Johns Road / Clearwater Avenue Intersection ................................. 34

Table 5-49: 2041 PM Without G2S Gardiners Road / Sawyers Arms Road Intersection .................... 35

Table 5-50: 2041 PM With G2S Gardiners Road / Sawyers Arms Road Intersection ......................... 35

LIST OF FIGURES

Figure 1-1 : Christchurch Motorway (RoNS) Projects ......................................................................... 2

Figure 2-1 : GCTS Area Priorities ..................................................................................................... 4

Figure 3-1 : Aerial Photograph of Study Area .................................................................................... 5

Figure 3-2 : Indicative Layout Plan of Gardiners / Sawyers Improvements ........................................... 8

Figure 5-1 : 2006 Base Intersection LoS ......................................................................................... 10

Figure 5-2 : 2011 PM Period Intersection LoS ................................................................................. 11

Figure 5-3 : 2011 AM Link Saturation .............................................................................................. 12

Figure 5-4 : 2011 PM Link Saturation .............................................................................................. 13

Figure 5-5 : 2026 AM Peak Flow Differences with G2S .................................................................... 19

Figure 5-6 : 2026 PM Peak Flow Differences with G2S .................................................................... 24



Figure 5-7 : 2026 PM Peak Ratio Volume to Capacity (no G2S) ........................................................ 25

Figure 5-8 : 2026 PM Peak Ratio Volume to Capacity (with G2S)...................................................... 25

Figure 5-9 : 2041 AM Peak Flow Differences with G2S .................................................................... 30

Figure 5-10 : 2041 AM Peak Link Travel Time Change with G2S ...................................................... 31

Figure 5-11 : 2041 PM Peak Flow Differences with G2S ................................................................... 36

Figure 5-12 : 2041 PM Peak Link Travel Time Change with G2S ...................................................... 36

Figure 5-13 : 2041 PM Peak Network Intersections LoS (no G2S) ..................................................... 37

Figure 5-14 : 2041 PM Peak Network Intersections LoS (with G2S) .................................................. 37

APPENDICES

Appendix A

Appendix B


Status: Final April 2013 Project No.: Z1818001 Page 1 Our ref: Johns ITA revC FINAL.docx

1 Introduction

1.1 Background

This Integrated Transport Assessment (ITA) is provided to consider and quantify the transportation effects of the State Highway 1 Johns Road (The Groynes to Sawyers Arms Road) improvement project. It is the intention that the report supplements the Notice of Requirement documentation that will be used by Christchurch City Council in their assessment of the aforementioned project. This ITA generally follows the guidance supplied in Research Report (RR) 442 – Integrated Transport Assessment Guidelines.

1.2 Project Description

1.2.1 Christchurch Western Corridor

The Western Corridor will upgrade and four-lane State Highway 1 (SH1) between Belfast and Hornby. The Western Corridor connects the northern and southern Canterbury areas with Christchurch International Airport, and runs between Belfast in the north and the large industrial area at Hornby in the south. Most of the traffic on the corridor is heading to and from Hornby or the airport, with only around 10% of the traffic travelling further to the south. The focus of the corridor upgrade is to four-lane SH1 from The Groynes to the centre of Hornby and provide a bypass of Belfast. Selected intersection improvements are programmed along this route.

The Western Corridor works are required for a number of reasons. Around 37,000 vehicles per day, among the highest for any road in Canterbury, use Main North Road through Belfast to enter and exit Christchurch. This number of vehicles, and in particular the trucks and heavy vehicles using the road, discourage walking and cycling and restrict public transport. As traffic volumes grow, congestion will become worse and safety and public health concerns will increase around the Main North Road/Belfast Area. Further along the corridor, increased commercial and industrial activity, particularly in Hornby and at the airport, is creating more traffic and congestion at peak times. There is insufficient capacity in the existing two-lane road to absorb further traffic growth. To ensure businesses based outside Christchurch are able to get their goods to and from the airport, commercial areas and industrial areas, the current road requires upgrading to reduce travel times (and travel times variability) and improve safety.

1.2.2 The Groynes to Sawyers Arms Road Four Laning

This ITA considers one section of the overall Western Corridor Project described above. Johns Road, between The Groynes and Sawyers Arms Road (G2S) will be widened to four lanes (two lanes in each direction) separated by a central median. The design includes a roundabout at Clearwater Avenue and the development of an adjacent one-way service road lane between Wilkinsons Road and Gardiners Road to minimise the number of properties with direct access onto the highway. The project length stops short of the existing Sawyers Arms Road roundabout. In addition, the project design seeks to improve safety at intersections by restricting traffic movements (principally right turns) across SH1, including:

• Gardiners Road: Where left turn only from Johns Road onto Gardiners Road, and left turn from Gardiners Road into the new service lane, will be permitted.

• Wilkinsons Road: Where only left turn out of Wilkinsons onto Johns Road and left turn from the new service lane into Wilkinsons Road will be permitted.

• Greywacke Road: Left into and out of Greywacke Road will be permitted. Right turns into, or out of, Greywacke Road will not be possible.



The project includes an improved road cross section with the provision of two lanes in each direction, central median and sealed shoulders, improved pedestrian and cyclist facilities, enhanced street lighting and improved environmental aspects (stormwater and landscaping). Ultimately, the key project aims are to improve safety and capacity along this section of the corridor which will benefit travel time and reliability to and from Christchurch International Airport, greater Christchurch and the wider Canterbury Region. In addition, a new link road is being investigated between Sawyers Arms Road and Greywacke Road, parallel to SH1. This link road will improve access to the businesses and land in this vicinity to the west of Johns Road.

1.3 National Context

The government has identified seven roads of national significance critical for ensuring access to significant markets and areas of employment and economic growth. Improving these roads will help grow the national economy by lifting productivity in New Zealand’s largest cities and surrounding regions. Making these key routes more efficient and safer will improve reliability of journey times, reduce severe congestion and improve key freight and tourism routes.

The Christchurch Western Corridor is one part of the Christchurch Motorway improvements package which forms one of the Central Government’s Roads of National Significance Projects (RoNS) that will improve access to Christchurch City, the International Airport and the Lyttelton Port of Christchurch (Lyttelton Port). It will also reduce congestion, improve safety and support economic growth.

Figure 1-1 : Christchurch Motorway (RoNS) Projects



2 Planning & Funding Context

2.1 National Framework

2.1.1 Government Policy Statement 2012

The Government Policy Statement (GPS) on Land Transport Funding sets three focus areas of:

• Economic growth and productivity

• Value for money

• Road safety

The GPS places particular emphasis on the importance of investment in the State highway network which includes the RoNS projects. Investing in these routes will ease the most significant pressure points in the national network, reduce congestion in and around the largest metropolitan areas, improve road safety and link major sea and air ports more effectively into the State Highway network.

2.1.2 National Land Transport Programme 2012-2015

The key themes of the 2012-2015 National Land Transport Programme (NLTP) are:

• Ensuring Value for Money

• Supporting Economic Growth and Prosperity

• Improving Safety

• Providing a range of travel choices

The 2012-2015 NLTP will provide a government investment of approximately $3.0 billion to the RoNS projects throughout New Zealand. The NLTP in Canterbury is focused on growing the regional economy and supporting the recovery of Christchurch. Investment is being made in infrastructure that will support the fast and efficient movement of product from the farm gate to the market. It is envisaged the Christchurch Motorways RoNS will be pivotal to supporting the city's redevelopment and assisting the export sector. The 2012-15 NLTP will see the completion of Stage 1 of the Southern Motorway and the investigation and design of the subsequent stages. This will improve links to Lyttelton Port. Approximately $40 million will be invested in Christchurch under this NLTP. Progress will continue on the SH1 Western Corridor to increase capacity on the city's western fringe and to provide an efficient connection to Christchurch International Airport. Ultimately, it is expected that these Christchurch RoNS projects will ease congestion, increase safety, reduce travel times and provide easier access to the city, Christchurch International Airport and the Port of Lyttelton.

2.1.3 State Highway Asset Management Plan 2012-15

The RoNS projects are committed within the State Highway Asset Management Plan as these projects have been specifically identified as addressing some of the most significant service gaps that exist within the state highway and land transport network. The RoNS investments will improve journey reliability and efficiency on nationally strategic roads, as well as providing enhanced safety.

2.2 Local Framework

2.2.1 Canterbury Regional Land Transport Strategy 2012-2042

The Canterbury Regional Land Transport Strategy echoes similar principles to the NLTP – two key objectives of the RLTS replicate those of the NLTP in delivering improved safety, as well as assisting economic development. These principles are fundamental components of the RoNS projects.



In addition, the Canterbury RLTS outlines the commitment to the RoNS projects in both the short term (1-3 years) and medium term (4-12 years) as the various projects throughout greater Christchurch are delivered through to completion. Capital investment in roading infrastructure will equate to over 30% of all regional expenditure for both the short and medium term.

2.2.2 Greater Christchurch Transport Statement (GCTS)

Within the GCTS, the Western Corridor is denoted as being one of the Greater Christchurch Area Priorities for airport access and overall freight growth and opportunities. Improving journey reliability, resilience and efficiency together with safety are key transport outcomes. Investment in the Western Corridor, led by NZTA and supported by other agencies such as CCC, Christchurch International Airport Limited (CIAL) and KiwiRail is noted in GCTS as being a top priority for the region.

Figure 2-1 : GCTS Area Priorities

2.2.3 Christchurch Transport Strategic Plan (CTSP) 2012-2042

The Christchurch Motorways projects are included within the CTSP as these improvements will support improving efficiency and reliability within the strategic road network and assist freight movement. This reinforces the overall vision as well as a number of goals within the Plan. The CTSP has a focus on economic vitality, safety and freight improvements which will be positively contributed to by the Western Corridor works.

3 Existing Situation

3.1 Network Description

SH1 between Belfast and Hornby is, currently, a combination of two and four lane sections as a result of some sections having been recently upgraded.



The current transportation network in the vicinity of the G2S project area (to which this ITA relates) is shown below:

Figure 3-1 : Aerial Photograph of Study Area

The key features of the existing route within the project area are:

• SH1: Approximately 4km in length, running from Sawyers Arms Road roundabout, to a point just north of the Clearwater Lane (Willowcreek Lane) intersection.

• Wilkinsons Road (Local Road): Forms a T intersection with Johns Road (south side) 1.2km north of Sawyers Arms Road. All movements into and out of Wilkinsons are currently available.

• Greywacke Road (Local Road): Forms a T intersection with Johns Road (north side) 1.4km north of Sawyers Arms Road. Greywacke Road is currently a short cul-de-sac proving access to a number of businesses. All movements into and out of Greywacke are currently available.

• Stella Close (Local Road): Forms a T intersection with Johns Road (south side) 1.6km north of Sawyers Arms Road. Stella Close is currently a short cul-de-sac proving access to a number of residential properties. All movements into and out of Stella Close are currently available.

• Gardiners Road (Minor Arterial): Forms a T intersection with Johns Road (south side) 2.1km north of Sawyers Arms Road. Gardiners Road is 3km long and runs south forming an intersection with both Sawyers Arms Road and Harewood Road. Gardiners Road serves residential properties and includes a section that is undeveloped and subject to an 80km/h posted speed limit. All movements into and out of Gardiners Road are currently available.

• Clearwater Avenue (Local Road): Forms a T intersection with Johns Road (north side) 2.7km north of Sawyers Arms Road. Clearwater Avenue is an access only road and serves the Clearwater resort as well as a number of residential properties. All movements into and out of Clearwater Avenue are currently available.

• Clearwater Lane / Willowcreek Lane (Local Road): Forms a T intersection with Johns Road (north side) 3.3km north of Sawyers Arms Road. Willowcreek Lane is an access only road that serves a small number of resident properties. All movements into and out of Willowcreek Lane are currently available.

Scheme Extent

Greywacke Road

Wilkinsons Road

Gardiners Road

Scheme Extent

State Highway 1 N



3.2 Existing Network Issues

Presently SH1 (Johns Road) is congested at peak times. The Annual Average Daily Traffic (AADT) for Johns Road for 2012 is recorded as 18,500 near to The Groynes and 21,000 in close proximity to Sawyers Arms Road. Such traffic volumes inevitably cause congestion during peak periods. The intersection of Johns / Sawyers Arms (roundabout with dual circulating lanes) is presently a key location of congestion along the corridor.

3.3 Non-Car Modes

3.3.1 Public Transport

Presently no bus routes use Johns Road within the G2S project length.

The 107 route does include a section of Gardiners Road between Hussey Road and Sawyers Arms Road.

No other public transport operates within close proximity to the project area.

3.3.2 Walking & Cycling

No pedestrian footpaths are currently available along the G2S project length. Whilst no specific counts have been undertaken, on site observations reveal that, at present, pedestrian movement along the corridor is minimal. In terms of crossing movements, again site observations suggest there is limited demand for such movements. This is potentially a result of the type of environment around this location where there are limited pedestrian attractors so demand is limited. Land use tends to be low density residential or commercial with limited customer trips to sites. Trips to the likes of McVicar Timber or Smith Cranes, due to the nature of these businesses is almost entirely motor vehicle based and not general public trips.

Cycling numbers along the existing G2S route are unknown. The current road layout is unlikely to be popular with cyclists as a result of the limited provision for cyclists – given the varying shoulder width throughout and lack of provision of intersections.

3.4 Safety Analysis

3.4.1 State Highway 1

The NZ Transport Agency Crash Analysis System (CAS) has been used to determine the crash history within the G2S project length for the most recent full five years (2008-2012). A collision diagram is provided in Appendix A, together with the crash details.

Table 3-1: Severity of Crashes

Year Fatal Serious Minor Non-Injury Total DSi*

2008 - - 2 3 5 -

2009 - 2 1 3 6 3

2010 - - 3 3 6 -

2011 - - 6 2 8 -

2012 - - 1 5 6 -

Total - 2 13 16 31 3

* Death and serious injury casualties



Table 3-2: Annual Distribution of Crashes

Crash Type Number of Reported

Crashes Percentage of Reported

Crashes

Head on 2 6%

Hit Object - -

Lost Control Off Road 7 23%

Lost Control On Road - -

Miscellaneous - -

Overtaking 6 19%

Pedestrian 1 3%

Rear End, Crossing 2 6%

Rear End, Queuing 2 6%

Rear End, Slow Vehicle - -

Crossing, Direct - -

Crossing, Turning 11 35%

Total 31 100%

Table 3-3: Crash Causation Factors of Reported Injury Crashes

Causation Number of Reported Injury Crash Causation Factors

Alcohol 6

Too fast 2

Failed giveway/stop 10

Overtaking 3

Incorrect lane/position 2

Poor handling 6

Poor observation 14

Poor judgement 7

Fatigue 3 * Note more than one factor may apply to a single crash

Table 3-4: Environmental Factors

Wet Dry Night Day Weekend (Fri 6:00PM to

Monday 5:59AM) Weekday

No. 5 26 10 21 5 26

% 16 84 32 68 16 84

Of the crashes occurring within the 4km project length:

• None were fatal, two were serious, thirteen were minor and sixteen were non-injury. • The predominant crash types were crossing with a vehicle turning (where the straight ahead

moving vehicle collides with the right side of a vehicle turning out of an intersection turning



right), together with lane change / overtaking and cutting in to left. Both of these types of movements resulted in 5 crashes.

• Two head on collisions took place • Four crashes involved crashes taking place during cornering manoeuvres • Two crashes were a result of loss of control

3.4.2 Local Road Network

On the basis that the G2S project could result in a migration of traffic to the local road network, the safety assessment has also considered the impact on the local road network.

The key intersection to be considered is that of Gardiners Road and Sawyers Arms Road. It is understood that this intersection has already been identified by Christchurch City Council as requiring an upgrade to traffic signals for safety purposes:

Figure 3-2 : Indicative Layout Plan of Gardiners / Sawyers Improvements

The crash history for this intersection has been analysed for the 5 year period 2008-2012. In this period there has been 2 serious, five minor and fourteen non-injury crashes at (within 50m radius of the centre of) this intersection. Of these 21 crashes, 19 (90%) were of the crossing (no turning) type where vehicles have failed to give way.

With the introduction of G2S, traffic patterns will certainly change as some movements onto and off Johns Road will no longer be available. Given this intersection currently exhibits a poor crash history, it would not be advisable for additional traffic to use this intersection with the current priority layout. However, given this will be upgraded to traffic signals then the limited traffic migration that will take place is not considered problematic. The forecast traffic effects are considered in Section 4 and, using this information, a conclusion regarding safety is provided in Section 6.2.

The effect of the G2S project on other intersections within the local network is discussed in Section 6.2.



4 Future Scenario

4.1 Assessment Years

To determine the network effects of the G2S project, the CCC CAST model (Saturn Software) has been used. This model has been used to assess the traffic effects for the horizon years of 2026 and 2041, with and without the works proposed in the G2S project as a comparison. In addition the base years of 2006 and 2011 (post-earthquake) have also been considered. CAST Version 5 has been used, incorporating a number of network modifications that have become more apparent since the 2011 model development. These are detailed in a practice note provided by QTP (see Appendix B). The future horizon years have included all of the proposed network changes and improvement projects scheduled to be completed throughout the model area (again these are detailed within Appendix B). For the ‘without G2S’ scenarios, all of the proposed projects are included within the model network, except for the G2S works. Therefore, the model scenarios considered are as follows:

• 2006 Base • 2011 Post EQ Effects • 2026 with / without G2S • 2041 with / without G2S

Time periods are peak hour (AM 0800-0900, PM 1630-1730). These peak hours are specifically modelled as a time slice within a two hour peak (where end conditions from the previous sub-period are fed into the next).

4.2 Model Output Data

Using the model runs described above, a variety of output data was created. This included:

• Actual Flows (for all modelled years and periods) • Actual Flow Differences (all years, all periods including daily flow) • Actual Flow Differences 2011 to Horizon Year (2026 & 2041 all periods) • Intersection Level of Service (all years, all periods) • Link Delay (all years, all periods) • Link Vehicle Hours Difference (all years with option) • Link Level of Service (all years, all periods) • Time difference per vehicle seconds per link (2026 & 2041 with option)

Not all of the information retrieved from the model is presented in the forthcoming sections – key information is drawn from the model outputs and presented accordingly.

5 Assessment of Traffic Impacts

5.1 Base Year 2006

The generic 2006 base model was run for the AM, PM and IP periods. The model runs provided actual flows throughout the network as well as link delay and intersection Level of Service. Of note was the LoS assessed for Greywacke Road in the PM peak period where side road delay was recorded as being 30-50 seconds per vehicle (LoS D).



Figure 5-1 : 2006 Base Intersection LoS

It is noted that the 2006 base year is almost obsolete given the re-routing of traffic following the Canterbury Earthquakes and the effect on the road network and trip generators and attractors.

5.2 2011 Post Earthquake Traffic

The CAST model was updated as a result of the changing travel patterns following the earthquakes. Therefore, it is considered that the 2011 is a more appropriate ‘base’ scenario to test and compare against. A number of different model runs were undertaken for 2011, to determine:

• Actual flows AM, PM, IP, Daily Total • Intersection LoS AM, PM, IP • Link Delay AM, PM, IP • Link Degree of Saturation (Volume / Capacity) AM, PM, IP

5.2.1 Intersection LoS

When considering intersection LoS, for the AM or IP period, there were no issues within the project area as modelled. For the 2011 PM peak period it is evident below that there is an issue at the Johns Road / Greywacke intersection with significant delays (>70 seconds per vehicle). However, this is likely to represent an issue with the model and a true representation is not portrayed. The right turn out of Greywacke has been manually removed from the model as it is not able to be modelled accurately due to the significant delay. Therefore this movement is shown with zero demand and therefore zero delay and LoS A. In addition to this flaw, the left turn out of Greywacke is shown as LoS F with actual delay within the model being hugely over predicted (over 2000 seconds per vehicle). Clearly the model does not adequately represent this operation of this intersection. No further intersection issues exist throughout the project area.

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Figure 5-2 : 2011 PM Period Intersection LoS

Further consideration of intersection LoS along the corridor reveals the following:

Table 5-1: 2011 LoS State Highway Network

Intersection Period Intersection

LoS

Worst Approach

LoS

Comments

Johns / Sawyers AM B B

PM B B

Johns / Wilkinsons AM B F Wilkinsons approach, major

delays left and right turn

PM D E Right turn from Johns into Wilkinsons creates delay

Johns / Greywacke AM A A

PM F F Right turn out

Johns / Gardiners AM B F Gardiners approach major delays left and right turn

PM B F Gardiners right turn to Johns 2

min delay

Johns / Clearwater AM A F Clearwater approach right turn

delays

PM B F Left and right turn out of

Clearwater

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Table 5-2: 2011 LoS Local Network

Intersection Period Intersection

LoS

Worst Approach

LoS

Comments

Gardiners / Wilkinsons AM A A

PM A A

Gardiners / Hussey AM A A

PM A A

Gardiners / Sawyers AM A C

PM A E Right turn from Gardiners south

approach

It is noted that the Johns/Sawyers Arms roundabout is indicated to operate at LoS B. However, higher delays are typically observed at this location during peak periods. This reflects difficulties in modelling multi-lane roundabouts, especially given the local traffic conditions in 2011, where the Johns Road approaches to this roundabout have a high degree of saturation (as noted in 5.2.3 below) which is likely to result in less efficient operation in reality than assumed in the model. This also indicates that performance of the roundabout for the future do-min years may be somewhat understated in the model (i.e. benefits of G2S scheme may be greater than is indicated by the model).

5.2.2 Link Delay

Link delay has been assessed for the 2011 year and no noteworthy issues exist.

5.2.3 Link Saturation

Link saturation was tested along the corridor for the 2011 period and the results for both the AM and PM peaks are shown below. The model output diagrams show anywhere where the volume to capacity ratio is near or above the 75% level, indicating the link is nearing or at its theoretical capacity. Note the numbers shown represent degree of saturation (volume / capacity).

Figure 5-3 : 2011 AM Link Saturation

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Figure 5-4 : 2011 PM Link Saturation

It is clearly evident above that there is a tidal flow along the SH1 corridor, with the majority vehicles heading south in the AM peak period and the reverse during the PM period. With the 2011 traffic flows, during the AM peak period, there is a small amount of available capacity along the SH1 G2S project length. However during the PM peak when vehicles are heading north, it is evident that much of the corridor is already over the 90% ratio of nominal capacity. This clearly demonstrates the need for additional link capacity along this length to cater for projected future traffic growth and is likely to already be causing traffic to choose alternative routes through the local road network to avoid the busy Johns Road.

5.3 2026 Design Year

The 2026 design year has been analysed, for a variety of periods and different parameters have been tested. The data is discussed below:

5.3.1 2026 Intersection LoS AM Period

All of the intersections within close proximity to the study area have been analysed for the 2026 design year with and without G2S. The information is presented below:

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5.3.1.1 Johns Road / Sawyers Arms Roundabout

Table 5-3: 2026 Without G2S Johns Road / Sawyers Arms Roundabout

Summary for Johns/Sawyers Arms Intersection 2026 AM Option 00a

From Demand1 Exit Flow V/C Delay

2 LoS Queue

Sawyers Arms Rd S Approach 301 300 14 14 B 0

Johns Rd E Approach 1664 1600 56 12 B 0 Sawyers Arms Rd N Approach 88 88 3 14 B 0

Johns Rd W Approach 1147 1145 35 13 B 0

INTERSECTION 3200 3133 43 13 B 1

Table 5-4: 2026 With G2S Johns Road / Sawyers Arms Roundabout


From Demand Exit Flow V/C Delay LoS Queue Sawyers Arms Rd S Approach 355 355 27 17 B 1

Johns Rd E Approach 2346 2337 100 128 F 77 Sawyers Arms Rd N Approach 87 87 3 14 B 0


INTERSECTION 3948 3938 74 82 F 77

Clearly there is a significant worsening of this roundabout with the proposed G2S project. This needs to be considered in the context of the overall SH1 improvements as with the increased capacity of SH1 with the G2S project north of this roundabout and the additional capacity improvements to the south, but with no improvements currently proposed for this specific roundabout, it becomes a bottleneck to the traffic which is able to travel to the roundabout relatively unconstrained. Without G2S the roundabout operates with an improved LoS but this is because traffic is constrained further up and down stream prior to the roundabout itself and there are better alternative routes. It is also important to recognise that Sawyers Arms Road will become a key access to McLeans Island Road via Broughs Road or Logistics Drive, with McLeans Island Road being closed down. The ‘Without G2S’ modelling outputs for this intersection should be treated cautiously; this model, like many others, struggles with modelling the performance of multi-lane roundabouts. As was noted in Section 5.2.1, the base model for the Johns Road / Sawyers Arms Road roundabout does not adequately represent the actual known operation. This issue is then replicated with the 2026 horizon year where a LoS B for all approaches with zero queue length is predicted, which is almost certainly false. Regardless of the level of confidence in the modelling for this intersection, the NZ Transport Agency are aware that this roundabout becomes a constraining factor and considerations have been made as to what form of improvements should be taken at this location. A full interchange has been considered in the past as an option to be further investigated.

1 Demand is defined throughout the tabulated modelling results as being vehicles per hour

2 Delay is defined throughout the tabulated modelling results as being seconds per vehicle



5.3.1.2 Johns Road / Wilkinsons Road Intersection

Table 5-5: 2026 Without G2S Johns Road / Wilkinsons Road Intersection

Summary for Johns/Wilkinsons Intersection 2026 AM Option 00a

From Demand Exit Flow V/C Delay LoS Queue

Johns Rd S Approach 847 846 53 3 A 0 Wilkinsons Rd E Approach 57 57 95 280 F 4

Johns Rd N Approach 1614 1600 100 45 E 4

INTERSECTION 2519 2503 84 36 E 9

Table 5-6: 2026 With G2S Johns Road / Wilkinsons Road Intersection



Johns Rd S Approach 916 915 24 0 A 0 Wilkinsons Rd E Approach 314 314 41 7 A 4

Johns Rd N Approach 1929 1929 56 1 A 4

INTERSECTION 3159 3157 45 1 A 9

Clearly the provision of the G2S project results in significant benefits in terms of the operation of this intersection, moving from a LoS E overall to a LoS A. This is directly attributable to the removal of right turning traffic. However, the Johns Road South approach (Without G2S) is mostly free flow and the LoS E relates to the Johns Road North approach and to Wilkinsons Road.

5.3.1.3 Johns Road / Greywacke Road Intersection

Table 5-7: 2026 Without G2S Johns Road / Greywacke Road Intersection

Summary for Johns/Greywacke Intersection 2026 AM Option 00a


Johns Rd E Approach 1614 1600 101 21 C 9 Greywacke N Approach 96 96 25 11 B 0 Johns Rd W Approach 874 872 47 2 A 0

INTERSECTION 2584 2568 80 14 B 10



Table 5-8: 2026 With G2S Johns Road / Greywacke Road Intersection



Johns Rd E Approach 1929 1929 51 0 A 3 Greywacke N Approach 96 96 8 4 A 0 Johns Rd W Approach 916 915 20 1 A 0


The operation of this intersection is marginally improved with the provision of G2S.

5.3.1.4 Johns Road / Gardiners Road Intersection

Table 5-9: 2026 Without G2S Johns Road / Gardiners Road Intersection

Summary for Johns/Gardiners Intersection 2026 AM Option 00a


Johns Rd S Approach 874 871 55 18 C 4

Gardiners E Approach 30 30 59 179 F 1


INTERSECTION 2505 2497 84 36 E 7

Table 5-10: 2026 With G2S Johns Road / Gardiners Road Intersection



Johns Rd S Approach 916 915 24 0 A 0 Gardiners E Approach3 0 0 0 0 A 0



Clearly the provision of the G2S project results in significant benefits in terms of the operation of this intersection, moving from a LoS E overall to a LoS A. This is directly attributable to the removal of right turning traffic.

3 The Gardiners approach in the Option (With G2S) shows zero demand as due to change in the network, there is no movement

out onto Johns Road. There remains a left turn in but this is via a free speed exit lane that should not constrain traffic or be subject to delay. This is the case for both 2026 and 2041 horizon years in both the AM and PM peak.



It is notable that the Johns Road north approach travelling southbound (continuing on Johns Road) is shown as LoS E in the ‘Without G2S’ scenario. This is a priority movement and should be unconstrained by any opposing flows or blocking back (the demand flow for the left turn into Gardiners from this approach is only 4 vehicles). Upon further investigation it would appear that this Johns Road north approach is displaying such poor intersection LoS as a result of the link capacities both upstream and downstream of this intersection being saturated by 2026 in the AM peak.

5.3.1.5 Johns Road / Clearwater Roundabout

Table 5-11: 2026 Without G2S Johns Road / Clearwater Roundabout

Summary for Johns/Clearwater Intersection 2026 AM Option 00a


Johns Rd E Approach 1605 1600 100 183 F 62 Clearwater N Approach 16 16 20 91 F 0 Johns Rd W Approach 864 862 53 2 A 0

INTERSECTION 2484 2478 83 120 F 63

Again it is noted that the model is showing a poor LoS for Johns Road on the eastern approach to Clearwater despite the straight ahead movement having priority and not being required to give way for other movements. Furthermore, the predominant movement (99% of vehicles) on this approach is straight ahead (rather than right into Clearwater) and therefore the predicted LoS F is reflects the very small number of right turn vehicles. As with the situation discussed in 5.3.1.4 above, the LoS on this approach is predicted to be poor as a consequence of link capacity both upstream and downstream being saturated and therefore restricting this movement through this intersection – so rather than being intersection performance, is instead link capacity delay.

Table 5-12: 2026 With G2S Johns Road / Clearwater Roundabout



Johns Rd E Approach 2124 2124 78 9 A 0 Clearwater N Approach 16 16 1 13 B 0 Johns Rd W Approach 818 817 29 14 B 0


The model predicts, with the provision of the G2S, significant improvements to the operation of this intersection moving from LoS F to LoS A. Some improvements here would certainly be realised with the improvements as a result of the change from a priority intersection to a roundabout layout which means that right turning traffic into and out of Clearwater are adequately catered for. Specifically the delay of right turning vehicles turning out of Clearwater reduces from 144 seconds per vehicle to 15 seconds. However, it is important to note the benefits are overstated within the model as the model predicts the situation in 2026 Without to G2S to be worse than in fact is likely. That said, with the intersection form improvements and increased link capacity as proposed, significant performance improvements could be expected.



Furthermore, it is important to recognise situations where the model outputs are overly precise and theoretical. In the ‘Without G2S’ scenario, the model outputs suggest that the Johns Road East approach is operating at LoS F. This is because the model assumes blocking back by right turning vehicles preventing eastbound (straight ahead) Johns Road traffic from proceeding. In reality, drivers would adapt their behaviour accordingly to minimise such issues (for example by using the sealed road shoulder to avoid stationary vehicles waiting to turn right). That said, the demand for the right turn is concerning and with the opposing flow limiting available gaps, the delays for right turners would be significant creating potential safety issues (with drivers minimum gap acceptance reducing to unsafe levels).

5.3.1.6 Gardiners Road / Wilkinsons Road Intersection

The LoS at this intersection remains at LoS A both with and without the G2S project.

5.3.1.7 Gardiners Road / Hussey Road Intersection

The LoS at this intersection remains at LoS A both with and without the G2S project.

5.3.1.8 Gardiners Road / Sawyers Arms Road Intersection

Table 5-13: 2026 Without G2S Gardiners Road / Sawyers Arms Road Intersection

Summary for Gardiners/Sawyers Arms Intersection 2026 AM Option 00a


Gardiners Rd S Approach 57 57 9 30 C 1 Sawyers Arms Rd E Approach 925 924 73 18 B 8

Gardiners Rd N Approach 858 856 91 103 F 17 Sawyers Arms Rd W Approach 423 421 27 10 B 4

INTERSECTION 2263 2258 70 49 D 29

Table 5-14: 2026 With G2S Gardiners Road / Sawyers Arms Road Intersection




Gardiners Rd N Approach 734 734 76 48 D 12 Sawyers Arms Rd W Approach 418 417 27 10 B 3

INTERSECTION 1995 1994 58 26 C 23

The model outputs also reveal that this intersection witnesses benefits resulting from the introduction of the G2S project. The Gardiners Road North approach improves from LoS F to LoS D and the overall intersection LoS improves from D to C. Ultimately this situation is because, without the G2S project, the delay on SH1 would become such that vehicles would divert to local roads. This is evidenced by the volume changes discussed in greater detail below.



5.3.2 Link Flows 2026 AM Peak

A key parameter in understanding the overall impact of the G2S project is to consider the change in link flows as a result of the G2S project. This is displayed in the model output below which clearly demonstrates that with the G2S project, in the AM peak period, a significant number of additional vehicles are routed onto the G2S project length, which has the effect of reducing the number of vehicles using the majority of the local roads such as Hussey Road, Gardiners Road and Highsted Street. There is a slight increase in vehicles along Claridges Road and Styx Mill Road, though this is not significant and the intersection of Gardiners Road and Styx Mill Road has been modelled and is shown to operate at LoS A in the AM peak period (with G2S). Indeed, the figure below clearly demonstrates that the provision of G2S has network-wide beneficial effects in moving traffic onto SH1.

Road lengths shown red below depict an increase in vehicles due to G2S, whereas green demonstrates a reduction on that section of road due to the provision of G2S.

Figure 5-5 : 2026 AM Peak Flow Differences with G2S

It is also noted that there is a potential route choice issue with the model showing significant increases in traffic on both Waimakariri Road and also Watsons Road and no change to SH1. It is likely that this relates to an inaccuracy in the model relating to the route cost for these two links being incorrectly coded. Clearly this will have an effect on the figures produced for the operation of the Sawyers Arms Road / Johns Road intersection.

5.3.3 2026 Intersection LoS PM Period

A similar process was undertaken for the PM peak period to determine the network wide effects of G2S during the 2026 horizon year. The pattern of the AM period is generally repeated where G2S provides operational improvements to both the state highway and local road network.

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5.3.3.1 Johns Road / Sawyers Arms Roundabout Intersection

Table 5-15: 2026 Without G2S Johns Road / Sawyers Arms Roundabout Intersection

Summary for Johns/Sawyers Arms Intersection 2026 PM Option 00a


Johns Rd E Approach 1233 1205 61 14 B 1 Sawyers Arms Rd N Approach 311 310 30 21 C 1

Johns Rd W Approach 2520 2475 100 21 C 6


Table 5-16: 2026 With G2S Johns Road / Sawyers Arms Roundabout Intersection



Johns Rd E Approach 1296 1270 45 12 B 0 Sawyers Arms Rd N Approach 582 555 104 143 F 21

Johns Rd W Approach 2020 1862 101 111 F 52

INTERSECTION 4836 4594 77 69 E 74

For the same reasons as detailed for the AM peak period, this intersection becomes saturated as traffic flow up and downstream becomes less constrained and additional traffic is attracted to the route.



Summary for Johns/Wilkinsons Intersection 2026 PM Option 00a


Johns Rd S Approach 1832 1599 100 46 E 0 Wilkinsons Rd E Approach 223 213 85 88 F 5


INTERSECTION 3094 2831 86 33 D 10









It is interesting to note that the option results in around 30% additional traffic through this intersection. On more detailed investigation this all relates to the SH1 flow as Wilkinsons remains constant – this is likely as a result of the improvements to the state highway drawing traffic from the wider network.



Summary for Johns/Greywacke Intersection 2026 PM Option 00a


Johns Rd E Approach 1039 1018 64 0 A 14 Greywacke N Approach 142 32 445 3800 F 89 Johns Rd W Approach 1860 1600 102 73 F 13

INTERSECTION 3040 2650 91 90 F 115




Johns Rd E Approach 1045 1023 27 0 A 5 Greywacke N Approach 109 109 31 14 B 0 Johns Rd W Approach 2838 2663 67 2 A 0


Without G2S, the Johns / Greywacke intersection operates at LoS F in the PM peak period. This is considerably worse than during the AM peak with right turning traffic into and out from Greywacke Road creating major delays. With the provision of G2S, during the 2026 PM peak period this intersection improves from LoS F to LoS A – as a consequence of removing the right turn movements and providing additional link capacity and catering for approximately 30% extra traffic.





Summary for Johns/Gardiners Roundabout 2026 PM Option 00a





INTERSECTION 3128 2750 80 18 C 5


Summary for Johns/Gardiners Intersection 2026 PM Option 01a


Johns Rd S Approach 2841 2672 70 0 A 0

Gardiners E Approach 0 0 0 0 A 0



5.3.3.5 Johns Road / Clearwater Intersection

Table 5-23: 2026 Without G2S Johns Road / Clearwater Intersection

Summary for Johns/Clearwater Intersection 2026 PM Option 00a


Johns Rd E Approach 1166 1143 71 5 A 0 Clearwater N Approach 32 32 52 160 F 1 Johns Rd W Approach 1847 1507 94 17 C 1




Table 5-24: 2026 With G2S Johns Road / Clearwater Intersection






The LoS at this intersection remains at LoS A both with and without the G2S project





Summary for Gardiners/Sawyers Arms Intersection 2026 PM Option 00a


Gardiners Rd S Approach 629 619 83 63 E 10 Sawyers Arms Rd E Approach 624 617 49 17 B 5

Gardiners Rd N Approach 239 232 31 34 C 4 Sawyers Arms Rd W Approach 1038 991 99 91 F 14

INTERSECTION 2531 2460 76 60 E 32




Gardiners Rd S Approach 476 469 68 42 D 8 Sawyers Arms Rd E Approach 683 677 45 14 B 5

Gardiners Rd N Approach 244 241 34 33 C 4 Sawyers Arms Rd W Approach 695 661 40 12 B 5

INTERSECTION 2098 2048 47 22 C 22



Again, the operation of this intersection is actually improved with the provision of G2S for the same reasons as the AM peak period – that is without G2S, delay on SH1 would be such that additional vehicles would utilise the local roads. With G2S there is a greater propensity for vehicles to use the State Highway. Again, this principle is demonstrated below in the flow differences diagram shown below.

5.3.4 Link Flows 2026 PM Peak

During the PM peak period change in link network flows is even more exaggerated than that of the AM peak. With the provision of G2S over 1000 additional vehicles transfer to the G2S project length resulting in significant reductions in vehicles travelling on a large part of the local network. It is therefore clear that the provision of G2S is highly beneficial for the overall network operation.

The routing issue south of Sawyers Arms roundabout is again obvious in the Figure below with SH1 showing a reduction in traffic and Waimakariri and Watsons shown with significant increases.

Figure 5-6 : 2026 PM Peak Flow Differences with G2S

The benefits of G2S are also further reinforced when link capacity is considered for the PM peak both with and without G2S. As can be seen below a number of the local road links are nearing capacity – most likely because access onto SH1 is limited as this too is saturated with vehicle travelling north.

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Figure 5-7 : 2026 PM Peak Ratio Volume to Capacity (no G2S)

However, with the provision of G2S, the situation on the local road network is improved considerably and this is shown in Figure 5-8 below:

Figure 5-8 : 2026 PM Peak Ratio Volume to Capacity (with G2S)

5.3.5 2026 Summary

It is evident that in traffic impact terms, the provision of G2S when tested at horizon year 2026 is essential in supporting the operation of the network both in terms of the state highway operation and also in ensuring the local network continues to operate in a suitable fashion. The only issue that has been identified through the comprehensive modelling work undertaken is the capacity (and consequential delay and rerouting of traffic) at Sawyers Arms / Johns Road roundabout. This intersection has been discussed earlier, and will be looked at in order to resolve the issue in due course.

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5.4 2041 Design Year

As with the 2026 design year, a similar process has been undertaken for the horizon year of 2041 with intersection LoS and link flows and capacity considered.

5.4.1 2041 Intersection LoS AM Period

No commentary is provided for each individual intersection as the general effects on each is the same as for 2026 though the volumes will change and this affects the actual LoS.

5.4.1.1 Johns Road / Sawyers Arms Road Roundabout

Table 5-27: 2041 Without G2S Johns Road / Sawyers Arms Road Roundabout



Johns Rd E Approach 1701 1600 57 12 B 0 Sawyers Arms Rd N Approach 84 84 3 14 B 0



Note - as with the 2011 and 2026 modelled scenarios for this intersection, the outputs for the Without G2S scenario should be treated with caution very unlikely to provide a true representation of intersection operation.

Table 5-28: 2041 With G2S Johns Road / Sawyers Arms Road Roundabout



Johns Rd E Approach 2359 2303 101 160 F 97 Sawyers Arms Rd N Approach 83 83 3 14 B 0


INTERSECTION 4119 4046 76 97 F 98







Johns Rd E Approach 1654 1600 101 34 D 15 Greywacke N Approach 95 95 30 14 B 0 Johns Rd W Approach 981 971 53 3 A 0

INTERSECTION 2730 2666 81 22 C 16


Summary for Johns/Greywacke Intersection2041 AM Option 01a


Johns Rd E Approach 1965 1945 51 0 A 4 Greywacke N Approach 95 95 8 4 A 0 Johns Rd W Approach 1032 1023 23 1 A 0






Johns Rd S Approach 953 944 59 3 A 0 Wilkinsons Rd E Approach 57 56 94 322 F 5


INTERSECTION 2663 2600 85 36 E 10











Summary for Johns/Gardiners Roundabout 2041 AM Option 00a





INTERSECTION 2645 2602 85 35 D 8










5.4.1.5 Johns Road / Clearwater Avenue Intersection

Table 5-35: 2041 Without G2S Johns Road / Clearwater Avenue Intersection



Johns Rd E Approach 1632 1600 101 201 F 70 Clearwater N Approach 16 16 19 90 F 0 Johns Rd W Approach 966 958 59 3 A 0

INTERSECTION 2614 2574 84 127 F 70

Table 5-36: 2041 With G2S Johns Road / Clearwater Avenue Intersection














Gardiners Rd N Approach 904 893 97 136 F 23 Sawyers Arms Rd W Approach 476 470 31 11 B 4

INTERSECTION 2377 2354 73 62 E 36







Gardiners Rd N Approach 817 814 86 62 E 13 Sawyers Arms Rd W Approach 469 462 30 11 B 4

INTERSECTION 2168 2155 64 32 C 25

5.4.2 Link Flows 2041 AM Peak

As with 2026, this assessment has also considered the overall effect on links in close proximity to G2S both with and without the project. The change in flows is shown in the figure below:

Figure 5-9 : 2041 AM Peak Flow Differences with G2S

Again it is clear that with G2S in place, significant numbers of vehicles divert from the local network to SH1. Whilst there are isolated spots of increases on the local network on certain road lengths (generally routes where vehicles are trying to access Johns Road), the vast majority of the local network sees a reduction in volumes (shown green) due to the significant increase in vehicles using SH1 with G2S in place. The link travel time was also assessed and the improvements to the local network with G2S in place are shown below:

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Figure 5-10 : 2041 AM Peak Link Travel Time Change with G2S

In the Figure above, the width of a line perpendicular to a link is proportional to the delay of that link (by direction). The links shown green demonstrate that, with G2S in place, travel time along these links has improved, when compared to ‘Without G2S’. Note also the main red link is caused by the delayed northern approach to Johns Road / Sawyers Arms Road intersection.

5.4.3 2041 Intersection LoS PM Period

As per the 2041 AM period, no commentary is provided for each individual intersection as the general effects on each is the same as for 2026 though the volumes will change and this affects the actual LoS.

5.4.3.1 Johns Road / Sawyers Arms Road Intersection

Table 5-39: 2041 PM Without G2S Johns Road / Sawyers Arms Road Intersection



Johns Rd E Approach 1326 1278 64 14 B 1 Sawyers Arms Rd N Approach 489 487 48 22 C 2

Johns Rd W Approach 2454 2387 100 38 D 17

INTERSECTION 4540 4418 79 28 C 20

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Table 5-40: 2041 PM With G2S Johns Road / Sawyers Arms Road Intersection



Johns Rd E Approach 1417 1365 47 12 B 0 Sawyers Arms Rd N Approach 656 590 106 178 F 29

Johns Rd W Approach 2003 1766 101 135 F 62

INTERSECTION 5076 4657 77 81 F 91


Table 5-41: 2041 PM Without G2S Johns Road / Wilkinsons Road Intersection



Johns Rd S Approach 1898 1600 100 45 E 17 Wilkinsons Rd E Approach 178 166 90 130 F 6


INTERSECTION 3254 2905 88 34 D 29

Table 5-42: 2041 PM With G2S Johns Road / Wilkinsons Road Intersection









Table 5-43: 2041 PM Without G2S Johns Road / Greywacke Road Intersection



Johns Rd E Approach 1178 1139 71 0 A 18 Greywacke N Approach 144 31 460 3811 F 90 Johns Rd W Approach 1925 1600 102 73 F 13

INTERSECTION 3247 2770 93 85 F 121

Table 5-44: 2041 PM With G2S Johns Road / Greywacke Road Intersection

Summary for Johns/Greywacke Intersection2041 PM Option 01a


Johns Rd E Approach 1149 1105 29 0 A 5 Greywacke N Approach 111 111 32 15 B 0 Johns Rd W Approach 2929 2664 67 2 A 0



Table 5-45: 2041 PM Without G2S Johns Road / Gardiners Road Intersection






INTERSECTION 3354 2886 83 19 C 6



Table 5-46: 2041 PM With G2S Johns Road / Gardiners Road Intersection







5.4.3.5 Johns Road / Clearwater Avenue Intersection

Table 5-47: 2041 PM Without G2S Johns Road / Clearwater Avenue Intersection



Johns Rd E Approach 1293 1247 78 6 A 0 Clearwater N Approach 33 33 53 162 F 1 Johns Rd W Approach 1914 1509 94 17 C 1


Table 5-48: 2041 PM With G2S Johns Road / Clearwater Avenue Intersection












Table 5-49: 2041 PM Without G2S Gardiners Road / Sawyers Arms Road Intersection



Gardiners Rd S Approach 691 675 90 84 F 11 Sawyers Arms Rd E Approach 651 632 52 21 C 5

Gardiners Rd N Approach 279 268 38 41 D 4 Sawyers Arms Rd W Approach 1053 999 98 106 F 18

INTERSECTION 2674 2574 78 73 E 38

Table 5-50: 2041 PM With G2S Gardiners Road / Sawyers Arms Road Intersection



Gardiners Rd S Approach 529 516 75 47 D 8 Sawyers Arms Rd E Approach 703 685 46 17 B 5

Gardiners Rd N Approach 244 239 35 32 C 4 Sawyers Arms Rd W Approach 767 702 46 13 B 5

INTERSECTION 2242 2143 52 25 C 23

5.4.4 Link Flows 2041 PM Peak

The change in link flows during the PM peak period in 2041 has also been considered. This is shown in the figure below:



Figure 5-11 : 2041 PM Peak Flow Differences with G2S

This highlights the critical role G2S will play in diverting traffic away from local roads and onto the state highway network. The hourly volume reductions are significant for the local network with hundreds of vehicles taken away from Hussey Road, Gardiners Road and Sawyers Arms Road, with G2S implemented. The link travel time comparison of without G2S and with G2S is also shown below:

Figure 5-12 : 2041 PM Peak Link Travel Time Change with G2S

The road lengths shown red along with the adjacent numerals show where G2S will increase travel times along that link, whereas the green road lengths and numerals show the travel time improvements along that length (seconds per vehicle). The figure above clearly demonstrates the network-wide positive effects that G2S is forecast to provide. Again, the dominant red line is the southern approach to Sawyers Arms Road / Johns Road roundabout.

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5.4.5 Overall Intersection LoS 2041 PM Peak

As a final check, the network intersections LoS plots were considered for the PM peak period for 2041 with and without G2S. These are provided below:

Figure 5-13 : 2041 PM Peak Network Intersections LoS (no G2S)

Figure 5-14 : 2041 PM Peak Network Intersections LoS (with G2S)

Clearly it can be seen above that the provision of G2S creates an overall positive effect on intersection LoS. Key changes are the intersections on Johns and Greywacke vastly improve with G2S with a consequential worsening around Johns / Sawyers Arms (which has been discussed and will be addressed in a separate project to this one). Furthermore, the situation on Sawyers Arms Road is actually improved for a number of intersections.

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5.4.6 2041 Summary

From the modelled data assessed and that presented above, it is clear that generally, similar patterns exist as to 2026 in respect of the effect that G2S will have upon the network (links and intersections). Given the additional traffic volumes, the 2026 results are exacerbated by 2041 with generally increased delay and worsened LoS.

6 Evaluation & Discussion

6.1 Network Impact

The overall effects of G2S throughout the modelled network are considered in detail in Section 5 above. As a result of the assessment and the modelling outputs, it is apparent that the general network effects of the G2S project are, on the whole, beneficial. This positive impact benefits both operation of the state highway network and also the local road network. That said, there are also some localised areas where the effects of G2S are negative, both in terms of additional vehicle flows and network performance. The effect that the overall SH1 improvements will have on Sawyers Arms Road (at Johns Road) roundabout have been shown to be considerable and will need to be resolved in future. No works are presently proposed at the roundabout (both the G2S project and the project immediately south do not provide any improvements to the current roundabout configuration) – however the NZ Transport Agency are aware that improvements to this roundabout will be required in due course. From a network operation perspective, the testing undertaken indicates G2S is beneficial and indeed critical to the effective operation of the state highway and local road network in close proximity. The improvements proposed will be fundamental in ensuring the expeditious movement of traffic around the network in the vicinity of the G2S project area.

6.2 Safety Evaluation

A qualitative safety assessment has been undertaken regarding the effects of the G2S project. This has involved considering the current trends of crash types, times and causation factors and considering what effects the proposed improvements will have. In relation to crash potential and safety on or in close proximity to SH1, it is considered that the proposed project will vastly improve safety for the following reasons:

• Removal of Conflicts: The majority of right turns have been removed (and one controlled)

• Improved Intersection Facility: Roundabout provision at Clearwater will provide a safer intersection form than the existing priority intersection

• Dual-laning: Providing greater overtaking opportunities

• Central Median: To physically divide opposing traffic streams

• Wider shoulders: To provide run out and recovery areas for vehicles, together with a safer location for breakdowns

• Provision of guardrail (wire rope barrier): Along central median and on higher risk locations to deflect vehicles that have lost control and avoid head on collisions

• Improved lighting: To improve visibility during the hours of darkness

When these improvement measures are considered against the 5 year crash record for the project length, it is assessed that the safety performance of this section of highway will improve. For example the removal of priority right turns will eradicate the right turn crossing crashes that currently take place. In addition, crashes that do still take place should be reduced in number and their severity also reduced – for example with the provision of wire rope barrier, head on collision should be reduced or prevented, whilst wider road shoulders will ensure some loss of control incidents do not result in a crash.



Whilst there is no proposal to increase the existing 80km/h posted speed, in reality with the improved road environment, the operating speed will increase. Generally, higher speed crashes result in greater severity, however given the significant improvements in the road environment, it is considered the overall improvement will result in a much safer road environment (and reduced number and severity of crashes). It is also noted that the ‘stop-start’, interrupted driving (that will become more prevalent in future years without G2S) will be improved which should further assist.

Given there was a propensity for right turn crashes, loss of control and overtaking type crashes, it is assessed that the G2S project will result in significant crash savings.

For the local roads, whilst there is some redirection of traffic, the data provided in Section 4 clearly demonstrates there is a minor effect (even a beneficial effect) on the local roads in close vicinity to the project. This is directly related to safety because intersections with poor LoS resulting in capacity problems and delay could result in greater conflict or drivers reducing gap acceptance to unsafe levels.

To provide some assurance, LoS was therefore calculated for a number of the internal road intersections as a broad indicator of operation. The intersections of Gardiners / Wilkinsons, Gardiners / Hussey and Gardiners / Styx Mill were also tested with G2S for the AM and PM peak periods for both 2026 and 2041. All intersections continued to operate at LoS A during both peak periods and both horizon years.

The Gardiners Road / Sawyers Arms Road intersection is already proposed to be upgraded with the provision of traffic signals. This new arrangement has been modelled in this assessment and demonstrated to work better from an operational perspective with, rather than without, G2S. With the upgrade to signalisation and the demonstrated acceptable operational performance, it is not considered that safety will continue to be a concern at this intersection

4.

6.3 Non-Motorised Road Users

While the project is primarily focused on improving the State Highway for motorised vehicles, the opportunity has been taken to provide improvements for pedestrians and cyclists where feasible. Cyclists are provided for by means of a wide sealed shoulder as well as off road provision at intersections. In addition, at the northern most end of the project, an off road cycle path is provided (commencing at Clearwater roundabout) that will link into the Western Belfast Bypass proposals and provide a completely segregated facility for cyclists.

For pedestrians, there is little demand for cross connectivity, nor would this be advisable given the nature of the route. The one location where pedestrian linkages may be worthwhile is around Clearwater and The Groynes and therefore pedestrian cut downs and tactile paving are provided at the Clearwater roundabout where traffic will be slowing on the approach to the intersection.

Overall it is envisioned that the improved layout will provide a step change improvement in both provision and safety for non-motorised road users.

7 Conclusion On balance, it is considered that the impacts of the proposed G2S project are primarily positive. It has been shown that there are already deficiencies in the operation of Johns Road which constrain it from performing its expected role in the local network. These deficiencies have also been shown to get worse over time if no interventions are put in place. The improvements will provide significant travel time, reliability and safety enhancements to the network which will serve to support the objectives of various national and regional transport strategies. Providing a safe, reliable and efficient road network is critical to the region and this project is critical to the overall Western Corridor and wider Christchurch Motorways RoNS projects.

4 It is possible that overall crash numbers may increase with signalisation as rear-end become more common – however

generally the overall severity of collision is reduced as the crash type changes and vehicle speeds are reduced.



It has been demonstrated that the safety and operational improvements do not come at the expense of the local network. In fact, the provision of G2S has been shown to improve the performance of the adjacent local road network. Failure to provide additional capacity on SH1 will result in significant congestion on both state highway and local roads, and the increased likelihood of traffic rerouting through local roads.

In addition to motorised vehicular traffic, the G2S project provides improvements for non-motorised road users. The road environment for cyclists will be significantly improved upon with wide sealed shoulders, off-road intersection provision and a separate cycle track. Pedestrian facilities on the route are limited due to the nature of the road and the limited existing or desired pedestrian usage or demand. However, facilities are provided at the location (Clearwater roundabout to access The Groynes) where some pedestrian activity may eventuate.

In summary, it is concluded that the G2S improvements are safe, essential and beneficial to the surrounding road network and can be accommodated without adverse effects to the local road network. Moreover, the provision of G2S, in combination with other associated SH1 improvements will assist in achieving both regional and national key transport objectives.



Appendix A



Johns Road (Sawyers to Groynes) Crash Data 2008-2012



Appendix B

Western Corridor – Groynes to Sawyers Arms CAST

Modelling

Appendix B QTP Note.Docx Ref: 2013-013

© QTP Ltd 2013

1 CAST Base Models

1.1 Overview

1.1.1 In–line with the project brief, this assessment has focused on two appraisal

years, being 2026 and 2041. The majority of planned major road

infrastructure is assumed to be in place within the ‘generic’ CAST model, as

summarised in Table 1.1, below.

Table 1.1: Schemes Included Within Future Year ‘Generic’ CAST v05

Model

CAST

ID Scheme Name

Yr

Introduced V05

18 Blenheim Road Deviation 2010 Y

19 Ferry Road Rd/Humphreys Dr Signals 2010 Y

20 SH1/Rolleston Dr/Hoskyns Rd Signals 2010 N

31 Halswell Junction Rd/Main South Rd Signals 2010 Y

50 Marshland Rd 4 Laning - Briggs Rd to QEII Dr 2010 Y

86 Bus Priority Corridor - Main North and Papanui Rd 2010 Y

157 Rolleston - Byron St Extension 2010 Y

179 Logistics Drive Extension (to Sawyers Arms Rd) 2010 Y

180 Prestons Rd Speed Reduction to 50kph (Waitikiri Corner) 2010 Y

193 Bus Priority - Hills Rd (North Avon Rd to Shirley Rd) 2010 Y

502 Pound Rd/Yaldhurst Rd Roundabout 2010 Y

506 Russley Rd/Yaldhurst Rd Signals 2010 Y

507 Dunbars Rd/Halswell Rd Signals 2010 Y

512 Johns Rd/Main North Rd Signal Improvements 2010 Y

514 QEII Dr/Travis Rd/Burwood Rd Signals 2010 Y

528 Harman St/Lincoln Rd Signals 2010 Y

509 Waimari Rd/Peer St Signals 2011 Y

4 Greers/Northcote/Sawyers Arms Signals 2016 Y

9 Marshland Rd/QE II Dr Signals 2016 Y

21 Ferrymead Bridge Widening 2016 Y

22 Ferry Rd 4 Laning - Aldwins Rd to Fitzgerald Ave 2016 Y

24 Wigram Rd Realignment (Awatea Dunbars Overbridge

Bridge) 2016 Y

25 Wigram Magdala link (Overbridge) 2016 Y

26 Lincoln Road 4 Laning - Curletts Rd to Wrights Rd 2016 Y

34 Western Corridor - Memorial to Yaldhurst 2016 Y

35 Western Corridor - Sawyers to Memorial 2016 Y

36 Western Corridor - Yaldhurst to Waterloo 2016 Y

43 Yaldhust Village Development Network (Living G) 2016 Y

46 Belfast Village Development Network (CN1 Applefields) 2016 Y

51 Northwood Blvd/Johns/Groynes Priority Intersection 2016 Y

60 Fernside Rd/Flaxton Rd Improvements (WDC) 2016 Y

79 Western Corridor - Groynes to Sawyers 2016 Y

93 Christchurch Southern Motorway (CSM1 only) 2016 Y

97 Aidenfield Overpass (CSM1) 2016 Y

154 Marshland Rd Speed Reduction to 70kph (Prestons Rd to

Belfast Rd) 2016 Y

162 Islington Park Drive Development 2016 Y

169 Belfast Industrial Development Network (CB1) 2016 N


Modelling


© QTP Ltd 2013

CAST

ID Scheme Name

Yr

Introduced V05

174 Pound Rd Deviation to SH1 (Close Barters Rd) 2016 Y

184 Wigram Development Network (CSW1) 2016 Y

186 Symes Rd Extention to Havard Ave 2016 N

187 Symes Rd Closure 2016 N

201 Rolleston Development Network 2016 Y

224 Ron Guthrey Rd/Peter Leeming Rd Signals 2016 Y

298 Western Belfast Bypass 2016 Y

301 Airport Southern Development Network 2016 Y

302 Pound Rd (Resa) Deviation 2016 Y

303 Yaldhurst Rd Speed Reduction to 70kph (Russley Rd to

Pound Rd) 2016 Y

305 Capital A Trumpet 2016 Y

503 Marshland Rd/Hawkins Rd/Lower Styx Rd Signals 2016 Y

505 Marshland Rd/Prestons Rd Signals 2016 Y

508 Halswell Junction Rd/Shands Rd Signals 2010 Y

511 Gardiners Rd/Sawyers Arms Rd Signals 2016 Y

515 Ohoka Rd/Island Rd (W Ohoka offramp) 2016 Y

516 Cashmere Rd/Centaurus Ave/Colombo St/Dyers Pass

Signals 2016 Y

517 Awatea Rd/Springs Rd Signals 2016 Y

518 Blenheim Rd/Matapo St Signal Improvements 2016 Y

519 Frankleigh Ave/Lyttelton St Signals 2016 Y

520 Hoon Hay Rd/Sparks Rd Signals 2016 Y

521 Seymour St/Shands Rd Signals 2016 Y

522 East Belfast Development Network (CN4) 2016 N

523 Highfield Park Development Network (CN5 & CN6) 2016 Y

524 Fulton Hogan Development Network (CSW4) 2016 Y

525 Prestons Development Network 2016 Y

526 Harewood Cycle Project - Nunweek Blvd to Highstead Rd 2016 Y

530 Aymes/Springs Intersection 2016 Y

603 Levi/Lowes and Jones Road intersection upgrade 2010 N

2 Hills Road Extension (via East Ellington Dr) 2021 N

3 Northcote Road 4 Laning - Sawyers Arms Rd to Main

North Rd 2021 Y

5 Northern arterial 2021 Y

6 Northern arterial Extension (QEII Dr to Cranford St) 2021 Y

7 QE II 4 Laning - Main North Rd to Innes Rd 2021 Y

29 Halswell Road 4 Laning - Curletts Rd to Dunbars Rd 2021 Y

87 Main North Road Narrowing to 2 lanes - Factory to QEII 2021 Y

94 Christchurch Southern Motorway (CSM1 and CSM2) 2021 Y

95 Main South Rd Four-Laning (MSRFL) 2021 Y

96 Rolleston SH1 Interchange MSRFL (Weedons Ross to

CSM2) 2021 Y

210 Cranford St 4 Laning - NAE to Innes 2021 Y

217 Northern arterial/QEII/Nortern arterial Extension Grade

Seperation 2021 Y

501 Deans Ave/Riccarton Rd Signals 2021 Y

504 Belfast Rd/Marshland Rd Signals 2021 Y

510 Travis/Bassett St Improvements 2021 Y

527 Marshes Rd/Shands Rd Signals 2016 Y

602 Tennyson St safety improvement 2021 N

306 Orchard Road Extension and Close McLeans 2026 N


Modelling


© QTP Ltd 2013

CAST

ID Scheme Name

Yr

Introduced V05

IslandRd/Johns Rd

601 Rolleston signal removal/overbridge 2026 Y

307 Harewood Left In - Left Out (Johns Rd) 2041 N

308 Sawyers Arms Interchange (Johns Rd) 2041 N

309 Hornby Bypass to Pound Rd 2041 N

604 Lincoln Southern Bypass 2041 Y

1.1.2 All but the final four CAST schemes listed above are introduced to the

generic CAST v05 future year model by 2026 and are therefore assumed to

be part of the ‘base’ network for this appraisal undertaken for both 2026

and 2041. We note the following changes to the assumed schemes within

the generic CAST v05 model adopted for this study:

• The proposed Hills Road extension is not intended to be part of the

‘generic’ CAST v05 model. It was, however, inadvertently retained

within the CAST v05 network from the CAST v02 network upon which

CAST v05 is based. For this study, it has been removed from the ‘base’

network.

• The Orchard Road extension to McLeans Island Road is not assumed

to be in place (coding of this scheme has been removed from the

generic CAST model). This scheme potentially removes the need for an

intersection at Mcleans Island Road / SH1 and as such is inconsistent

with the NZTA scheme plans for the Western Corridor.

• The Harewood Rd / SH1 Left In, Left Out scheme has not been

assumed in the base model for this study as logically it is reliant on

implementing the Sawyers Arms Interchange.

• The Hornby Bypass to Pound Rd has not been included. Instead, the

Southern Airport Access scheme proposed by the NZTA has been

assumed.

• The Pound Rd and Waterloo Road realignment schemes have been

included within the do-minimum 2026 CAST model. The proposed

modifications to the road network, including a new signalised T-

intersection at Pound Rd / Main South Rd have been coded based on

plans forwarded by the NZTA.

1.2 Modifications to CAST v05 Networks

1.2.1 The latest available version of Council’s CAST Model has been used as the

basis of the appraisal presented within this report, being CAST version 5,

as documented within the report ‘CAST V05 Model Update Report’ issued

on 10 May 2012.

1.2.2 Since the CAST model was issued, a number of relatively minor issues

have been noted during the course of its application to project appraisal.

The following changes have been made to the generic CAST models for

this study, most of which are fairly minor in nature:


Modelling


© QTP Ltd 2013

• The Tram Road / SH1 On-Ramp priority intersection has been modified

to include a ‘clear exit’ for right turns from Tram Road west (they do not

need to give-way to the left turners from Tram Road east). This

oversight in the base model coding only became apparent in the V05

update of CAST because the change to the New Zealand give-way

rules was introduced in CAST v05, which meant in previous versions

the right-turners from Tram Road west were getting priority over the left-

turners. The ‘issue’ is that in CAST v05 the right-turners suffer an

unrealistically high delay in the 2041 AM peak model. The coding of a

‘clear exit’ overcomes this issue.

• The eastbound through-movement on Brougham Street at its

intersection with Selwyn Street was coded in v05 as being available for

lanes 1 to 3 (i.e. the left-most lane was modelled as being for left

turning vehicles and through vehicles). This has been corrected to

restrict the through movement to lanes 2 to 3 only. This is a minor

issue as the saturation flow for the through movement was correctly

modelled as being representative of two through-lanes in CAST v05.

• The coding of merge priority markers for offside give-way movements

from minor roads intersecting with the one-way streets in the central city

has lead to some model instability (convergence issues). The merge

priority marker is used in preference to the give-way priority marker

where give-way movements need only give-way to traffic in the

nearside lane on multi-lane roads. The algorithms employed within the

SATURN software mean that merge turns should not be coded where

they give-way to more than one traffic movement (in this case, right-

turns from the one-way streets in to the minor arms, in addition to the

through-movements on the one-way streets). In correspondence with

the software author, the coding employed in CAST v05 will, in future

versions of the software, generate a serious warning or error. For this

study, merge turn priority markers in these situations have been

changed to give-ways (16 instances).

• The Plan Change 22 development spine road and proposed

intersections with Main North Road and Radcliffe Road have been

coded in to CAST. In most cases, where information is available

indicating proposed road networks associated with Greenfield growth

areas these have been coded in to the CAST v05 models. This ‘spine’

road was overlooked.

• The proposed Cashmere Road / Hoon Hay Road signals associated

with residential development at the Cashmere and Worsleys zonings

identified within the City Plan has been introduced in to the 2021 CAST

model

• The Belfast Area Plan Spine Road has been added to the model and is

assumed to run between a new roundabout at the Belfast Road / Blakes

Road intersection and a new roundabout on Main North Road between

the Christchurch Southern Motorway / Dickeys Road intersection and


Modelling


© QTP Ltd 2013

the Marshland Road / Spencerville Road intersection.

• A minor alteration has been made to modelling of roads and zone

loading in the suburban area of Burnside.

• The recently completed Halswell Junction Rd / Shands Rd signalised

intersection upgrade coding has been modified to reflect the lane

configuration constructed.

• It is understood that CCC, NZTA and Selwyn District Council have

reached an understanding that the east facing ramps to be provided at

Springs Rd / Halswell Junction Rd as part of CSM2 are to be provided

for all traffic. Previous assumptions had been that the ramps would be

for heavy vehicles only.

• As part of the ongoing upgrades (4-laning) of SH1 to the west of

Christchurch, the right-turn from SH1 southbound in to Ryans Road has

been removed.

• The recently constructed (but at the time of writing, not yet operational)

traffic signals at SH73 Yaldhurst Road / Yaldhurst Village Spine Road

have been incorporated into the future year model.

• The Moorhouse Avenue U-Turn movements on approach to Colombo

Street have been incorporated in to CAST.

Hazeldean Business Park PO Box 13-249 TEL +64 3 366 7449

6 Hazeldean Road Armagh FAX +64 3 366 7780

Addington, Christchurch 8024 Christchurch 8141 www.mwhglobal.co.nz

Addendum_ob review1.docx

MWH Ref: Z1818001

14 June 2013 Melinda Smith Christchurch City Council 53 Hereford Street Christchurch 8154 Attention: Melinda Smith Dear Melinda, Johns Road (Groynes to Sawyers Arms Road) Integrated Transport Assessment – Addendum to ITA This letter is intended to provide an addendum to the previously supplied Johns Road (Groynes to Sawyers Arms Road) Integrated Transport Assessment (dated April 2013). Your transportation specialists have raised two further queries relating to the transportation effects of the Johns Road (G2S) project and our response is provided below: 1. Increased traffic using Sawyers Arms Road & Gardiners Road

CCC have stated the expectation that increased traffic will use Sawyers and Gardiners due to the turning restrictions at the intersections of Johns/Wilkinsons and Johns/Gardiners. Certainly, intuitively this would be my expectation. However, this is not evidenced within the modelling undertaken. The modelling suggests that without the G2S improvements traffic flows will increase on Sawyers and Gardiners regardless. An example of this is show below:

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Figure 1: Change in link flows 2011 to 2026 AM Peak (no G2S)

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Figure 2: Change in link flows 2011 to 2026 AM Peak (with G2S)

In fact, for the AM peak period according to the modelling at least, the traffic flows on both Sawyers Arms Road will remain generally stable both with and without G2S. The situation in the PM peak is somewhat different.

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Figure 3: Change in link flows 2011 to 2026 PM Peak (no G2S)

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Figure 4: Change in link flows 2011 to 2026 PM Peak (with G2S)

In the PM peak period by 2026, the modelling suggests that the traffic on Sawyers will remain generally similar with or without the G2S improvements. However, the situation is improved on Gardiners where significant vehicle numbers are routing through the local network without G2S. That said, it is recognised that modelling has its limitations and does not always accurately represent the true reality of what would likely take place. Therefore as a sensitivity check, we have considered link capacities in the 2026 horizon year.

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Figure 5: Link Capacity (Volume/Capacity Ratio) 2026 PM Peak (no G2S)

Figure 6: Link Capacity (Volume/Capacity Ratio) 2026 PM Peak (with G2S)

The V/C cut off for display in the modelling is 70%. Clearly the link saturation (using volume over capacity as the indicator) is significantly improved on both Gardiners and Sawyers with the provision of G2S. It is expected that this situation occurs as a result of traffic no longer choosing to divert from the state highway (due to the state highway being much less congested with G2S improvements). 2. Sawyers Arms Road / Highsted Road Intersection Operation CCC have requested the ITA consider the operation of the Sawyers Arms Road / Highsted Road roundabout.

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The modelling outputs are provided for 2041 AM and PM peak periods below. The horizon year of 2041 has been selected as being the ‘worst case scenario’ for analysis purposes. Note the green solid sphere represents average intersection delay of 0-30 seconds (Level of Service LOS A - C), and the orange spheres represent average intersection delay of 30-50 seconds (LOS D).

Figure 7: Intersection Level of Service 2041 AM Peak (no G2S)

Figure 8: Intersection Level of Service 2041 AM Peak (with G2S)

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Figure 9: Intersection Level of Service 2041 PM Peak (no G2S)

Figure 10: Intersection Level of Service 2041 PM Peak (with G2S)

Clearly the modelling for both the AM and PM peak periods demonstrates the intersection of Sawyers / Highsted operates better with G2S than without. Again, it is expected that this is most likely the result of less vehicles diverting through the local network once the state highway upgrade has been undertaken (and congestion reduced). If you have any questions please do not hesitate to contact me on 341 4748.

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Yours sincerely

Jamie Povall Senior Engineer MWH New Zealand Limited

Documents

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