Neither Labour nor National are keen to talk about the climate change impacts of building new roads, even though transport planners say an increase in private car use is an inevitable outcome.

On Monday, National unveiled a $25 billion transport plan, including building more than 150 kilometres of four-lane highways around the country. About one fifth of the money is dedicated to bus and rail projects, while the remainder goes to roads.

While the policies are designed to ease congestion and boost economic productivity, long-time transport planner Axel Downard-Wilke – who is also a Green Party member – says this ignores a fundamental tenet of road-building: Induced demand.

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New projects can ease congestion for a short time, but they also incentivise people to drive by making getting in the car easier than other transport modes, Downard-Wilke says.

“It was in the 1950s that a planner said, ‘Building more roads to prevent congestion is like a fat man loosening his belt to prevent obesity’. We have known about this for decades.”

Consider the Katy Freeway in Houston, Texas, which was widened to a whopping 26 lanes between 2008 and 2011 at a cost of US$2.8 billion. Yet, over the three years after the expansion, morning commute travel times increased by a third and evening travel times by more than half.

Katy Freeway, Houston, Texas. Photo: WikiMedia Commons

In the era of climate policy, Downard-Wilke says incentivising people to get in their cars doesn’t just have a traffic impact but an emissions one too.

“Any party which is committed to building more roads is engaging in climate denial.”

National’s rebuttal to this is our cars soon won’t be burning petrol or diesel, but run on clean electricity instead.

Paul Winton, a transport policy expert and founder of the 1point5 Project, says vehicle electrification alone won’t get us to the targets consistent with keeping warming below 1.5C.

“At a national level we have a target of a 6 percent reduction in transport emissions by 2030, which EVs could get to,” he says. “But Auckland has set a target aligned with the science of 64 percent by 2030, which can’t be done just by buying electric cars.”

Or rather, it could be done, but would cost in the order of $60 billion for the vehicles alone. That’s not a serious proposal, which is why councils and the Government have both set targets for getting people out of cars (reducing vehicle kilometres travelled) and into buses and trains or onto bicycles or their own two feet.

New public and active transport projects are actually effective at reducing car congestion, because they have the opposite effect of induced demand. When it’s just as convenient to take the bus with a couple of dozen other people as it is to hop on the motorway in your own car, chances are you end up taking the bus at least some of the time. That cuts congestion for other drivers, reduces carbon emissions and – if you’re walking or cycling – is healthier.

Which makes it particularly depressing, Winton says, that National’s document doesn’t add any new cycleways or walking paths beyond what the Government is already planning.

The total emissions impact of the new roads in the plan, according to a Newsroom analysis of induced demand calculations by transport consultancy MRCagney, would be in the order of 327,000 tonnes of carbon dioxide a year with the current makeup of the fleet. That’s nearly the equivalent of eight weeks of coal-burning at the Huntly power station.

While that figure will decline as the fleet decarbonises, EVs will still represent less than one in six cars in New Zealand in 2030, even under the Climate Change Commission’s ambitious pathway.

Asked about these impacts, National’s transport spokesperson Simeon Brown says the party is committed to meeting New Zealand’s climate goals.

“Over the coming decades, what we drive might change as more New Zealanders make the switch to electric vehicles, but we will still need modern, fast, high-quality roads to drive on. Assessing the expected emissions impacts of new roads when we get to government will be part of the work officials do in delivering these projects.

“If you look at the top five countries in the world with the highest quality roads – Singapore, the Netherlands, Switzerland, Hong Kong and Japan – they have all seen their emissions fall over the last 20 years.”

Winton cautions his criticisms of National aren’t meant to suggest Labour is doing enough. Chris Hipkins scrapped some of the vehicle kilometres travelled targets in the “policy bonfire” earlier this year and the Government has also done work on new four-lane motorways, though not as many as proposed by National.

When asked about the climate impacts of the new roads in National’s plan, Transport Minister David Parker didn’t answer the question and instead said he liked some of the roads proposed by National. His issue was more with what he described as botched costings of the policy.

Chris Hipkins acknowledges road-building comes with a climate cost, but isn’t prepared to do without more of them.

“We’re trying to have a balanced transport policy as a government, that recognises that people do need to be able get around and roads are part of the way people get around, but that we also need to be reducing our overall emissions,” the Prime Minister said on Monday.

All-in-all, Winton says, Labour and National are battling it out to do not very much on transport. With climate target deadlines looming in 2025 and 2030, there’s little time to waste on cutting transport emissions, he says.

Marc Daalder is a senior political reporter based in Wellington who covers climate change, health, energy and violent extremism. Twitter/Bluesky: @marcdaalder

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