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christchurch sourthern motorway 2 banner

Project introduction

The Christchurch Southern Motorway Stage 2 is part of a package of projects designed to address increased travel demand and congestion in the south of Christchurch and Canterbury.

  • Estimated project cost

    $195 million
  • Project type

  • Project status


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Latest project video

February 2019 drone footage

There has been some good progress made on the Christchurch Southern Motorway Stage 2 (CSM2) project. The video shows excellent footage of the various new bridges, including Waterholes Road Bridge, Trents Road Bridge and the Weedons Road Bridge.

Please note that in order for the project team to continue the construction of the Weedons Interchange, Weedons Road will be closed at the SHI (Main South Road) intersection for approximately six weeks from 19 February 2019. Once this work is complete, the new south bound on-ramp will open to provide access from Weedons Road to SH1.



Project details

The NZ Transport Agency is working to provide better access to and from the south of Christchurch, the city centre and Lyttelton, by improving the capacity, safety and alignment of the Christchurch Southern Corridor.

Traffic congestion will only worsen in this area over the next few decades, due to growth in the south and southwest, if significant improvements to road capacity are not made. For this reason the Transport Agency is upgrading the Southern Corridor into the city. The first part of this project, The Christchurch Southern Motorway Stage 1 was completed in December 2012.

The Christchurch Southern Motorway Stage 2 (CSM2) is made up of a new section of four-lane median separated motorway, from Halswell Junction Road to SH1 near Robinsons Road and an upgrade of the existing Main South Road (SH1), from north of Robinsons Road to near Rolleston, to four lanes.

While planning these projects, we have listened to input from local communities and stakeholders to ensure the highway meets the needs of its communities. We have also worked with the Christchurch City Council, Selwyn District Council and Environment Canterbury to ensure our plans complement the whole south Christchurch and Canterbury road network and that the network provides transport options for all road users (drivers, pedestrian and cyclists).

Frequently asked questions

  • What are the benefits of the project?

    The project will provide better access in and out of Christchurch and this will in turn improve the economic well-being of the Canterbury Region and the wider South Island.

    Planned growth in the Selwyn District (such as the Izone industrial park, and Rolleston) requires improved access to the Christchurch CBD, key employment centres and Lyttelton Port.

    Without the project traffic on Main South Road is likely to double in the next 15 years, making access and crossing Main South Road very difficult and unsafe. The project will halve travel time between Rolleston and Christchurch at peak-times (from around 30 down to about 15 minutes). We also expect a 40% reduction in fatal and serious crashes.

    The project will reduce the high traffic volumes on State Highway 1 (Main South Road) through Templeton by separating local traffic from traffic heading to Lyttelton Port and the central city. There will be 2000 fewer trucks a day.

    Less traffic travelling through many local communities is also expected to improve accessibility and reduce noise, vibration and other potential effects from large volumes of traffic. The resulting improved highway and roading network will allow passenger transport to operate safely and more efficiently on Main South Road and Springs Road. Reduced traffic on many local roads will also improve conditions for pedestrians and cyclists, and allow the local councils to implement their own improved cycle strategies.

    The project will increase employment, both during construction and as a result of improved access. It will also play a positive role in Canterbury’s earthquake recovery.

    Hornby is one of the key industrial areas of Christchurch and the present (and future) congestion on roads in this area, such as Halswell Junction Road, means access for businesses in this area is difficult and inefficient. The project will help improve economic productivity through reduced transport times and costs. The construction of this project is also expected to create additional jobs.

  • What are the next stages for the project?

    The construction contract was awarded to the Downer/McConnell Dowell joint venture in August 2016. The contractors are determining the programme of works currently. Enabling construction works have begun in parallel. The project will probably take about 3 to 3.5 years to build.

  • What facilities are there for cyclists and pedestrians?

    Traffic moving onto the new section of motorway will reduce the number of vehicles on Main South Road through Templeton and on other local roads making it safer for cyclists and pedestrians, particularly around the communities of Templeton, Hornby and Prebbleton.

    The project will include a cycle/pedestrian shared path linking the Christchurch Southern Motorway Stage 1 cycle/pedestrian shared path with the existing Little River Rail Trail.  

    All local road bridges and underpasses will cater for cyclists and pedestrians to maintain access between local communities.

    We are also joining forces where we can with the Selwyn District Council and their plans to improve the local cycle network. One example of this is planning safer cycle access between Weedons Road and Templeton using Jones Road and the new access roads we will be building in this area.

  • Why was this alignment for the new motorway chosen?

    After the first round of consultation held in October – December 2010, we continued to investigate alignments for the new section of motorway taking into account the feedback received from the community. Many respondents wanted us to investigate a more northerly option. In response to this feedback, we drew up an alternative alignment that passed to the north of the intersection of Marshs and Shands Road. This alignment option was assessed alongside the 'best fit' option of the alignments originally identified in the October 2010 newsletter.

    Using the standard environmental and engineering assessments there was little to separate the alignment options. In the end our selection was based on two main factors; potential future land use and land cost.

    The northerly option was significantly more expensive as well as having a greater impact on the development of future industrial and business land identified in the Greater Christchurch Urban Development Strategy. For these reasons we chose an alignment within the study corridor as proposed in October 2010.

  • Why does a section of the Main South Road (SH1) need to be widened as part of this project?

    The four-laning of Main South Road (SH1) is essential because of the planned growth in Selwyn District (the Izone Industrial Park and Rolleston in particular) and the resulting growth in traffic. The four-laning project will provide efficient access to Christchurch from the south reducing potential bottleneck delays that could occur where the four-laned Christchurch Southern Motorway joins the existing two-lane SH1. The four-laning will also increase safety for all highway users.

  • How will the Transport Agency purchase a property needed for the project?

    The Transport Agency negotiates on a willing-buyer, willing-seller basis to purchase property at market value. The Transport Agency will pay for a valuation as well as any legal fees involved in the transaction and will also contribute to removal costs.

    The Transport Agency purchases land through an independent agent to ensure transparency and fairness. Compensation for directly affected landowners and occupiers will be provided under the Public Works Act. Further details of this process are available in the publication Landowner's rights – when the Crown requires your land for a public work, available from Land Information New Zealand.(external link)

  • What is a grade-separated interchange?

    A grade-separated interchange is where one road remains at ground level (at grade) while the other road passes over (or under) via a bridge (or in a trench) with on and off ramps. This type of intersection allows drivers to turn left and right or go straight on from any direction. (This type of intersection usually allows traffic driving straight on along the main road to continue uninterrupted) A grade-separated interchange is planned at the Shands Road interchange and Weedons Road interchange.

  • What will the final motorway look like?

    It will look similar to Christchurch Southern Motorway Stage 1. The motorway will have two lanes in each direction, separated by a central median with a wire rope safety barrier. There will be no direct access from private properties onto the motorway. Landscaping for the project is designed to complement the existing environment and is expected to be similar to the Christchurch Southern Motorway Stage 1 landscaping, while acknowledging the generally rural environment of CSM2. The project has a gently curving alignment open to views of the Southern Alps and Port Hills.

  • How will road noise be addressed when complete?

    Low-noise asphalt will be used along the majority of the new motorway. This is a quieter surface than the current chip-seal used on Main South Road. Noise reducing fences will also be used in some specific locations.

  • What will be done to minimise construction effects?

    It is the job of the contractor building the motorway to ensure construction and related environmental effects are dealt with in compliance with consent conditions. They are required to have plans outlining how they will deal with:

    • temporary traffic management
    • noise and vibration
    • dust management
    • existing soil contamination
    • erosion and sediment control
    • aquifer protection
    • accidental discovery (heritage and cultural).
  • How will effects on terrestrial ecology be managed?

    The project will result in minor loss of habitat for bird and lizard populations. Experts believe the birds will easily adapt and move to similar habitats nearby. We have designed new habitats along the motorway for lizards to minimise any adverse effect.

  • How will cultural effects be managed?

    A Cultural Advisory Group (CAG) has been set up, with help from Mahaanui Kurataiao Ltd (MKT), to obtain input from local rūnanga (groups) during development of final designs.

  • What will happen to stormwater?

    Rainfall running off the road will be collected in a stormwater system made up of mainly swales (wide grassed channels) and basins. This system will be designed to treat the water through natural processes minimising the impact on the local environment. We plan to minimise the use of pipes to increase the potential for soakage into the ground where appropriate.

  • How will this project affect local roads?

    We  expected an overall reduction in traffic on the surrounding network once the motorway is constructed. However, traffic on some roads (arterial road connecting to the highway) may well increase. We are working with Selwyn District Council to see where we can minimise potential negative effects on local roads.

  • What about stock-water races?

    The project design will include places where stock water races will be piped under the motorway. The disruption to the supply in the stock water races will be minimised by working closely with the Selwyn District Council and existing users.