Wellington Scoop

Billion dollar motorway – Transmission Gully now costing an extra $191million

Report from RNZ
The cost of Wellington’s Transmission Gully roading project has blown out by another $191 million. The Transport Agency has settled a dispute with the joint venture builder by agreeing to pay the extra sum and avoid costly and lengthy legal action.

It says the cost blowout was because of delays and the need for extra earthworks. The original cost was $850m.

The 27km four-lane motorway north of Wellington will be a major new arterial route into the capital. It is now due to be open before Christmas, months later than expected.

It’s the first Private Public Partnership in New Zealand for a state highway, which means it is being financed, designed, constructed and maintained by the private sector on behalf of the public sector.

Transport Agency interim chief executive Mark Ratcliffe said the financial settlement would ensure Transmission Gully was completed to a high standard.

“Progress has been slower than anticipated due to a number of issues encountered during construction including the Kaikoura earthquake in 2016, which diverted resources and materials,” he said.

The Agency said the extra money had come from the National Land Transport Fund and would not affect any other projects.


  1. Hamish Rutherford, 15. February 2020, 8:35

    Not a great look for proponents of PPPs. [via twitter]

  2. Alana, 15. February 2020, 8:39

    More mess from National’s not-so-effective former Transport Minister Simon Bridges.

  3. Neil Douglas, 15. February 2020, 18:32

    The construction cost of Transmission Gully must be over $3 billion including agency costs. It has never been $850 million! Only the reporters at the DomPost keep trying to tell us minions that it is $850 million based on a calculation only Treasury economists could understand (discounting the consortium’s payments over 20 odd years at 8% back to an irrelevant year pre 2016, blah blah blah………).

  4. Chris Horne, 15. February 2020, 21:52

    Construction of the Transmission Gully Motorway has had devastating effects. It destroyed mature kohekohe/nikau forest in Te Puka valley, destroyed natural land-forms by massive earthworks and dumping of soil and rock along the road, realigned Te Puka Stream and Horokiri Stream. The result has been massive inflows of sediment into Porirua Harbour’s Pauatahanui Inlet, a wetlannd of International Wildlife Importance. Construction machinery and other vehicles have poured untold volumes of greenhouse gases into the atmosphere as the world faces catastrophic climate change.

    Once opened, TGM will flood Wellington’s CBD with cars with nowhere to park, while undermining patronage on the environmentally benign Kapiti Line’s trains.

  5. TrevorH, 16. February 2020, 15:31

    I can’t wait for Transmission Gully to open. Four lane expressways are so much safer – we need one all the way to Auckland and Whangerei. The road toll would be cut in half and productivity would be hugely improved.

  6. Tye Blackstone, 16. February 2020, 15:49

    Trevor: productivity would not be improved through the unneeded Transgression gully. Out of curiosity, when you use the word productivity what is it that people are producing ? It’s such a waste of money.

  7. N.D., 16. February 2020, 22:07

    TrevorH – TG is a two lane carriageway with a crawler lane for trucks on the long steep sections (I’m betting loaded HGVs will avoid TG because of the gradients). We are not at L.A. standards yet (thankfully).

  8. Guy M, 18. February 2020, 5:01

    Chris Horne – re “Once opened, TGM will flood Wellington’s CBD with cars with nowhere to park” – you know, I’m not so sure. Trans Gully will certainly encourage more cars from Kapiti to get onto the highway and head towards the city, but the same existing road layout will continue to exist between Linden and Ngauranga Gorge, thus meaning that they will likely continue to clog the motorways the same as they do now.

    Certainly it may mean a faster trip home for those car commuters, as they will be gone from the Coast highway and will avoid traffic jams at Mana, Pukerua and Paekakariki – but on the trip into town, while avoiding those pinch points, i think the car drivers will find they are just going to hit their clog point at Linden and still have the same problems as always. I reckon that many people will try it in a car, but end up going back to the train.

    The crucial thing is that NZTA do NOT provide a second Terrace Tunnel, as that is the part that would really create traffic havoc in town. It has been carefully designed to limit the flow of cars into the city – a status that needs to be preserved.

  9. John Rankin, 18. February 2020, 18:05

    @GuyM: what you say is only half the story. To quote a recent advert for a medium density development in Whitby, “Transmission Gully is set to transform Wellington’s property market by unlocking a new lifestyle in the heart of the region’s northern growth corridor.” The development promises “direct access to Transmission Gully and into Wellington in approximately 20 minutes”.

    As far as I can tell, this development and others like it are devoid of public transport options, so we are creating a whole new generation of car-dependent suburbs. The housing is medium density, so this new generation potentially adds more cars per hectare than the previous one.

    The advert’s promise, “One benefit of the government’s investment in Transmission Gully is reduced commuting times between Whitby and Wellington City”, may be as fanciful as the artist’s impressions of the future subdivision.

    Presumably, NZTA has modelled likely future traffic volumes.