Tunnel under Wellington a Musk-have?
An ambitious idea to build the country’s longest tunnel under Wellington has prompted questions around cost and feasibility, but one expert suggests it could be done – it just may need a little help from tech billionaire Elon Musk.
Yesterday, Transport Minister Simeon Brown said the Government had asked NZTA Waka Kotahi to prepare advice on a longer tunnel option – a 4-kilometre tunnel with two lanes of traffic each way between the Terrace Tunnel and Wellington Rd in Kilbirnie.
The option would save up to 15 minutes on journeys to the airport, compared to just three minutes from a second Mt Victoria tunnel.
Transport expert Greg Pollock, who is the former head of Metlink and Transdev, said the long tunnel seemed like a “great idea” and he was pleased to see the Government looking into it.
Diverting the traffic around the edge of the city would make it a nicer place to live without congestion. “We get our city back, hats off to
“Tunnels are technically feasible anywhere, it all boils down to affordability.”
Ian Brown, geological engineer
the Government,” Pollock said.
The longer tunnel was a “far superior” option to building a second Mt Victoria tunnel – which was the original option the Government had said it would investigate, and which Brown said remained the priority.
Pollock said the longer tunnel was better because it could be built with less disruption and it would not shift the congestion problem further down the road.
While seismic issues would present a challenge for the tunnel, Pollock did not believe it was insurmountable. He pointed out that
Japan, another country prone to earthquakes, had several road tunnels underground – the Yamate Tunnel, Japan’s longest, is 18.2km. “We can bring in the right international experts,” Pollock said.
But Ian Brown, of geological engineering company Ian Brown Associates, said tunnels performed “incredibly well” under earthquake loading and while earthquake resilience would be the first thing people would be asking about, he didn’t have any concerns.
“Tunnels are technically feasible anywhere, it all boils down to affordability.”
The length across the city wasn’t an issue, but it would need to be ventilated and therefore may potentially need multiple entry points. A two-lane tunnel would be easier to manage, rather than Auckland’s Waterview tunnel, which is three lanes.
There was a question mark about depth, as residential foundations in Aro Valley, particularly high rises, would be 15m to 20m.
“I think we know the geology pretty well, there’s not much to be done there in terms of overall feasibility,” said Brown, “you could do [that survey] pretty quickly.
“There will be building foundations you don’t want to mess around with [and] there is always interesting issues over access, you’ll need to get a designation, I would have thought, to go under properties.”
Asked about the manpower in New Zealand to build what would be the country’s longest tunnel, Brown said while there were contractors here who would have that capability, “a big enough project would get international interest”.
“If you have a big enough job, they will come.”
He highlighted The Boring Company, owned by billionaire tech entrepreneur Elon Musk, which touts itself as a futuristic quickbuild tunnel solution for electric cars and people on wheels. Musk reportedly launched the company after becoming stuck in Los Angeles’ infamous traffic.
While the company’s Las Vegas project “Hyperloop” appears to have been beset with health and safety issues, according to overseas reporting, Brown said it was “a really fascinating story”.
“Ask the minister – tell the minister, he could get Elon Musk to build it.”
Mayor Tory Whanau, while concerned about climate change impacts, said she would be interested in looking at opportunities for the city, “in terms of freeing up surface-level road space for housing, walking, cycling and public transport as well as any urban development opportunities”.
“We need to offer people more low emission ways of getting around and lessen the number of cars on the road, which reduces congestion and frees up our streets.”
Councillor Diane Calvert was also on board with the new tunnel, saying it was an idea that had been considered since 2016.
“You move the traffic away from the central city that doesn’t want to be there ... This is what creates more space for pedestrians, and dare I say it, bike lanes.”
A tunnelled motorway would be dearer, but it could be tolled, she said. It would free up the space along Vivian and Ghuznee streets, as well as the waterfront quays.
Other local leaders were not sold on the benefits. Regional councillor Thomas Nash questioned how much the tunnel would free up congestion. Just 30% of drivers coming into the city on State Highway 1 would use the tunnel, according to Let’s Get Wellington Moving’s analysis in 2021, as most were heading into the city.
Using the cost per metre of the most recent quote for a second Mt Victoria tunnel ($1.4 billion for 623m), the 4km-long tunnel would cost $9b. That was before accounting for the difference between tunnelling underground and through a hill.
There was also the problem of induced demand, a pattern observed in transport changes where adding more vehicle lanes increases the number of people driving, eventually leading to congested highways again. “It would be nice not to have state highway traffic in town, but we know traffic fills the gap.”
The NZTA investigations would be “just one more report onto the pile” of discarded transport plans, Nash said.
City councillor Iona Pannett also believed it was an addition to the “decades of plans” for new motorways in Wellington that had not moved ahead, and an addition to the constant arguing between more roads and more public transport. The plan was “very 20th century”, she said, and the city needed to focus on “more modest aspirations”, rather than large and costly projects.
Māori ward councillor Nīkau Wi Neera said the tunnel was “a solution looking for a problem”. The Government should focus on the real issues in Wellington, especially the performance of the bus and rail network, he added.
Car-centric infrastructure, like new motorways, was short-sighted and would not sufficiently cater for Wellington’s growth, Wi Neera said. “Cars are incredibly inefficient at moving masses of people, and result in choked, unfriendly and congested cities.”
Labour’s transport spokesperson, Tangi Utikere, said the announcement was a diversion from “the important investments that need to be made today”, including new Cook Strait ferries and public transport subsidies.
“It is irresponsible. If National was truly focused on improving productivity, helping people get around and transporting freight, they would not be making these decisions.”