Transmission Gully nearing completion

December 08, 2021
  • Construction and commissioning
  • Project announcements

Skill, innovation, expertise and lots of hard work

New Zealand’s new motorway, Transmission Gully, is getting closer to being ready to open.

First proposed more than 100 years ago, Transmission Gully will be the main route in and out of Wellington. It is one of the most significant infrastructure projects ever undertaken in New Zealand.

The key rationale for building this road was to provide a safer and more reliable journey for motorists.

The route, while spectacular, required complex engineering and large-scale earthworks due to  the rugged terrain.
Twenty-five bridges were constructed, and the largest of these, Te Ara a Toa (Bridge 20) over Cannons Creek, stretches 230 metres in length and sits 60 metres above the valley floor.

Jason Spears, Managing Director of CPB Contractors, applauded the efforts of everyone involved in safely delivering the motorway to this point.

“Almost 8,000 people have worked on Transmission Gully, and I want to thank every one of them. This is a project that came with a lot of complex engineering challenges, and required the application of skill, innovation, expertise, and lots of hard work. It is an iconic project, and I’m very proud of the CPB team that delivered it for the people of New Zealand.” 

  The Transmission Gully motorway will:

  • Increase road capacity and passing opportunities
  • Provide a more reliable and safer journey for motorists and one that is better able to resist and recover from earthquakes and storms
  • Provide another route between Wellington and the lower North Island
  • Reduce traffic congestion and improve safety within communities like coastal communities such as Plimmerton and Pukerua Bay, by significantly reducing through traffic
  • Reduce fuel costs and contribute to economic growth

Some key facts about the construction of this iconic motorway:

  • 27 kilometres long
  • Six years to construct
  • 11.4 million cubic metres of earth excavated/moved
  • 660,000 tonnes of aggregate brought to site
  • 104,000 cubic metres of concrete used
  • 7,900 tonnes of reinforced steel used in bridges and other structures
  • Over 115,000 tonnes of asphalt laid
  • 25 bridges and large culverts
  • Longest bridge: Te Ara a Toa – 230 metres
  • Highest bridge: Te Ara a Toa – 60 metres
  • Largest cutting: Pouāwhā – Wainui Saddle – 70 metres high
  • 534 hectares of ecological mitigation and replanting (includes 2.5 million native trees and plants)
  • Eight streams modified/diverted

Read more about Transmission Gully here.

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