More than 90% of commuters want a faster Transmission Gully, including the Transport Minister, but a long-touted speed limit increase will not happen any time soon.

Ahead lies a summer of disruption on the $1.25 billion motorway project, with 20km needing to be rebuilt over the next six months, while transport officials continue to work through a bureaucratic process to consider the speed increase.

The 27km motorway remains technically unfinished, despite opening to the public in March 2022.

A 110km/h speed limit has long been on the cards for the road, with new figures released by the NZ Transport Agency Waka Kotahi (NZTA) showing overwhelming public support for an increase.

Public consultation between May and July this year received 2071 responses on increasing the limits for Transmission Gully and Raumati Straights.

Of those responses, 92% supported an increase while only 5% were against. The rest had mixed views or were unsure, figures released under the Official Information Act reveal.

Transmission Gully. Photo / Mark Mitchell

Transport Minister Chris Bishop told the Herald that “like over 90% of submitters, I’m keen to see it happen”.

Bishop spoke at an event in Porirua last month to launch a report by Infrastructure New Zealand into the benefits of the route.

Advice provided to Bishop before the event by NZTA warned he risked being asked about the status of the speed limit increase.

The agency told Bishop it was undergoing a legal process as required, but also raised “known road surface and roughness issues”, which appear to be holding up progress.

“The actual risk profile of these issues on raising the speed limit to 110km/h is being evaluated as part of the speed limit review.”

Prime Minister Christopher Luxon and Transport Minister Chris Bishop announce speed increases on 38 roads around New Zealand. Photo / Mark Mitchell

Those issues are at the centre of a rework programme, spelling daytime lane closures and full closures at night over summer while 20 lane kilometres of the 27km highway are resurfaced as part of finishing the road.

NZTA‘s website states the full decision-making process on a speed increase can take up to between six and 12 months, depending on scoping, design, and funding for necessary infrastructure.

That decision must be made independently by the agency’s director of land transport, Brent Alderton.

It is unclear how long it will take for the limit to go up once the decision has been made.

“The speed limit for both Transmission Gully and Raumati Straights remains at 100km/h until this process is complete”, NZTA’s website states.

The Infrastructure NZ report found Transmission Gully shaves an average of nine minutes off trip times, has healthier injury statistics, and delivered $79 million in savings in 2024.

“Travel times are shorter and more reliable throughout the day, for both the new road and the old route. Travel time savings range from a median of five minutes across the day, up to 31 minutes in peak times on the most congested days,” the report said.

Nobody has died on the stretch of motorway since it opened, and the rate of serious injuries per million vehicles has fallen from 0.6 on the old route to 0.2 on Transmission Gully.

Plans for Transmission Gully stretch back more than 100 years. Construction officially began in September 2014, when Prime Minister John Key turned the first soil on the project.

It was built under a public-private partnership (PPP) by the Wellington Gateway Partnership (WGP), with NZTA, CPB Contractors, and HEB Construction subcontracted to carry out the design and construction.

Then-Prime Minister Dame Jacinda Ardern, alongside former ministers Grant Robertson and Michael Wood during their stand-up after the Transmission Gully opening ceremony. Photo / Mark Mitchell

The road’s opening was down to the wire in March 2022 and was made possible only after NZTA agreed to defer some quality assurance tests until after the opening, and reduced the requirements for others.

After years of budget blowouts and Covid-19 delays, severe weather events, and the Kaikōura earthquake, there was a desire to get the road open and to iron out any problems later.

It was officially opened by then-Prime Minister Dame Jacinda Ardern and is used by almost 25,000 vehicles a day.

Ethan Manera is a Wellington-based journalist covering Wellington issues, local politics and business in the capital. He can be emailed at [email protected].