Parts of road surface on $1.25 billion Transmission Gully highway melt in summer sun

The Transmission Gully Motorway was opened in 2022 despite remaining incomplete. Photo / Mark Mitchell

Wellington’s beleaguered Transmission Gully motorway has had to receive urgent repairs after chunks of the road began to melt and peel off.

The $1.25 billion highway opened in 2022 but remains technically unfinished and is currently undergoing $32 million of rebuilding and drainage works.

Photos posted to social media yesterday show large patches of the road surface ripped up as motorists queue on the motorway.

In a statement, a spokesman for the NZ Transport Agency Waka Kotahi (NZTA) confirmed there were “some noticeable issues” with about 180m of the existing chipseal road surface “peeling off due to the heat and volume of slow or stopped traffic”.

That section was repaired overnight, while the wider stretch between Paekākāriki and the State Highway 58 interchange is due to have its southbound lanes resurfaced later this month, despite being less than four years old.

“When there are higher temperatures and slow traffic, there is always a risk of bitumen sticking to tyres – which is also what happened yesterday,” the spokesman said.

Chunks of the road surface of the $1.25b Transmission Gully peeled off, sticking to car tyres yesterday. Photo / Facebook

The area reached a high of 23.8C yesterday, according to MetService.

NZTA earlier said resurfacing work must take place over summer as it requires warmer weather.

The Herald revealed in October that years of work are required to rebuild the highway, which has never been completed despite opening in 2022.

A budget of $32m has been allocated for the “summer maintenance season”, but it won’t spell completion of the highway, with NZTA confirming future rebuilding and resurfacing is needed for future summers.

A source familiar with the project told the Herald work could continue for five years, a claim NZTA would not directly address when asked.

“Resurfacing and rebuilding work will continue on Transmission Gully as part of future summer maintenance seasons. The specific work programme for future seasons has not been finalised,” a spokesman for the agency said.

The road was built under a Public Private Partnership (PPP), but incomplete works ended up being the subject of legal action in the High Court between NZTA and the private road-builders.

The matter was ultimately settled outside court in late 2024, with the ongoing operations and maintenance being brought in-house by the agency.

The $32m rebuild now underway is funded as part of the PPP arrangement and will conclude mid-February.

The road, the construction of which had been debated for more than 100 years, was officially started in 2014.

The build’s setbacks included years of budget blowouts and delays due to Covid-19, severe weather events and the Kaikōura earthquake.

The works will help bring the highway up to standard for a speed limit increase to 110km/h, something more than 90% of commuters support.

Ethan Manera is a Wellington-based journalist covering Wellington issues, local politics and business in the capital. He can be emailed at ethan.manera@nzme.co.nz.