Transmission Gully marks one year of being open

More than eight million journeys have been taken on Transmission Gully in the year it has now been open.

As well as the journeys, Waka Kotahi said 8760 hours of continuous monitoring has been done by the Transport Operations Centre.

Several items have also been lost, including a car bonnet, a Maserati personalised number plate and a wheelie bin.

The 27-kilometre route is about 10 minutes quicker than the old highway, now redesignated State Highway 59.

It had been a long time coming - the idea for Transmission Gully first appeared in the newspaper, The Evening Post, in the year 1919.

Nearly 100 years later, John Key turned the first sod in 2014. The then-prime minister told the media: "It's been a long time coming."

Another eight years on, delayed by storms, the Kaikōura earthquake, Covid-19, and a huge underestimation of the earthworks required, it finally opened at the end of March 2022.

The new route bypasses Porirua, Paekakariki and Pukerua Bay, and local businesses feared they would be left for dead.

But the manager of Paekakariki's Beach Road Deli, Madison Arraj, said it was busier than ever.

"In terms of people coming into Paekak, we're just still getting busier and busier," she said.

Instead of a stopover, it had become "this amazing destination".

The turnoff to Paekakariki used to sit on the shoulder of State Highway 1, and Arraj said the cafe staff saw near-misses almost daily.

"That intersection was super, super dangerous. Every day you'd hear cars screeching on their brakes, that sort of thing - pretty close calls."

In her five years at the deli, she had called emergency services to report six crashes.

Porirua Mayor Anita Baker said the decrease in through-traffic along the coast had made Porirua's roads quieter and safer, too.

"It's reduced the traffic flows between Paremata and Pukerua, so it's a lot quieter, residents are really enjoying it, there's no hum on the road," she said.

"And there's more people actually using Transmission Gully and coming into the city."

She said more people were choosing to live up the coast, thanks to the shorter commute.

The road has already proven its worth in making the coast more resilient, after a slip on the old coastal route closed SH59 for about six weeks.

Transporting New Zealand chief executive Nick Leggett agreed.

"There have been fewer accidents, Transmission Gully is safer, [and] there's obviously been less congestion [on the old route]."

He said 75 percent of heavy vehicles were now using Transmission Gully.

Trucks tended to use more petrol climbing the Wainui Saddle, but the benefits of a safer, quicker trip, outweighed that.

Ventia, the company which manages the highway, said there have been 56 accidents and more than a kilometre of safety barriers have been crashed into and replaced.

In the years before opening, media reported regularly on cost blowouts and legal battles, as the Public Private Partnership broke down.

Originally meant to cost $850 million, the final bill ended up being more than $1.25 billion.

Leggett said it had been worth it, but the region's transport network still needed some work.

"We do need that Petone to Grenada, that east-west connection, the Hutt Valley needs its cross-valley link, and we need more investment in public transport, particularly rail services," he said.

Cellphone reception still cut out in two spots along the highway, but the Rural Connectivity Group said it was confident it could have four new cell sites working by the end of next year to fill the gaps.