The New Zealand Transport Agency has issued a promise: Come hell or highwater, Wellington's Transmission Gully will be open for motorists next September.
Photo: RNZ / Dom Thomas
It came as reporters were taken on a behind-the-scenes tour of the 27km highway, which has been beset by delays.
NZTA Waka Kotahi says the arterial route was supposed to cost $850 million but the budget has blown out now, costing $1.25 billion, and there have been delays.
The Wellington Gateway Partnership is responsible for the financing, design and construction of Transmission Gully and its operation and maintenance for the next 25 years, and chief executive Sergio Mejia said that without Covid-19, the road would already be in use.
He said the project was on track to be open by next September, and there were very few things that would stand in its way.
"Inclement weather, seismic events. It's pretty much what affects rolling projects like this.
"I am certain we are going to hit target. We are fully committed and we are on schedule."
Photo: RNZ / Dom Thomas
He cited the pandemic as the major reason the April 2020 date was not met.
Constructing Transmission Gully has meant 25 bridges or culverts had to be built to carry motorists from the Kāpiti Coast into Wellington.
The largest is Te Ara o Toa - or bridge 20 - which stretches more than 200m over Cannons Creek.
On the Wainui saddle, the sheer scale of the project becomes clear. Hilllsides have been gouged out and a stream moved 30m to allow the billion-dollar highway to take shape, with giant earth walls up to 95m deep.
The terrain is also earthquake prone and mostly farmland, meaning culverts had to be dug under roads to allow farmers access to their land.
Photo: RNZ / Dom Thomas
NZTA senior manager Andy Thackwray said the project was one of the country's most complex yet.
"It's the most challenging, the most complex and, yes, most expensive project.
"We have had the Kaikōura earthquake, adverse weather and the pandemic to contend with."
He said he was confident the project would hit its September opening date. With the project now 85 percent complete, Mejia says it was nice to think the end was in sight.
"I can see the light at the end of the tunnel. I can't wait until September 2021."
Some construction will continue this Christmas, but motorists shouldn't face extra disruption, aside from the usual snail's crawl out of the capital.
But come Christmas 2021, he Transport Agency promises drivers a smooth ride, on the highway through the hills.