About the Transmission Gully project
What is the Transmission Gully project?
The Transmission Gully project is a project to build a 27-km four-lane (two in each direction) motorway from MacKays Crossing to Linden (through Transmission Gully). There will be interchanges connecting the route to State Highway 58 and Kenepuru with a connection to Kenepuru Drive. In addition, there will be two link roads from the eastern Porirua suburbs of Whitby and Waitangirua to the route. The Porirua City Council will be the authority responsible for the Whitby and Waitangirua link roads. The project entails protection or relocation of utilities including transmission towers.
Why build Transmission Gully?
Transmission Gully project will provide:
- A safer road: four-lane route with central median barrier, with additional crawler lanes on the steepest section.
- Reduced likelihood of landslides, floods and damage to the highway from a major storm or earthquake.
- Quicker reinstatement than the existing State Highway 1 in the event of a major earthquake.
- Peak period travel time savings estimated at around 10 minutes per vehicle for Kapiti to/from Wellington, 15 minutes Kapiti to/from Hutt, five to seven minutes Porirua to/from Hutt Valley.
- Easier access from State Highway 1 to Porirua and Hutt Valley with shorter and more efficient freight movements to and from Seaview/Gracefield, Wingate and the Wairarapa.
- Important arterial connections for residential and light commercial areas in Porirua east to the SH network.
How will the Wellington region benefit?
The Transmission Gully route will:
- Provide an alternative strategic link for the Wellington region which will improve regional road network security.
- Assist in remedying the safety concerns and projected capacity problems on the existing State Highway 1 by providing a safe, reliable and more responsive route between MacKays Crossing and Linden in an environmentally responsive manner.
- Assist in enabling wider economic development by providing a cost-optimised route that better provides for the through-movement of freight and people.
- Assist in the integration of New Zealand's land transport system by enabling the existing State Highway 1coastal route to be developed into a safe multi-functional alternative to the proposed new strategic link.
In August 2012, the Minister of Transport directed the NZ Transport Agency (NZTA) to assess the suitability of using a Public-Private Partnership (PPP) procurement model to design and build the highway.
Following an extensive business case analysis (using the Treasury’s better business case framework), the NZTA determined that the project meets the Treasury’s criteria for a PPP procurement model.
On 21 November 2012, the Cabinet gave the NZTA approval to finance and build the Transmission Gully highway using a PPP. The NZTA was also given approval to borrow up to the estimated costs of traditional procurement as part of the PPP. Final approval of the borrowing limit will be confirmed by the Cabinet before the NZTA awards the PPP contract.
The following are the expected key stages and timelines for establishing a PPP for the Transmission Gully project:
- November 2012 (Announce Registration of Interest: To identify consortia interested in and capable of delivering the required services)
- January 2013 (Announce Expression of Interest: Potential consortia are asked to provide information on their capability to do the work)
- April 2013 (Identify shortlist of PPP consortia)
- Mid-2013 (Issue Request for Proposal: Formal bids on the project requested from the shortlisted consortia)
- End-2013 (Request for Proposal closes)
- Mid-2014 (PPP contract awarded)
Construction would begin by late 2014 and the highway would open for traffic by 2020.