The real cost of cars

At the moment a big chunk of the transport policy that isn't focused on building roads is focused on decarbonising the vehicle fleet, via policies like the clean car standard, feebate system, and scrappage scheme. The underlying justification for this is the need to rapidly reduce greenhouse gas emissions. That's vital, but at the same time it looks like we've been missing the elephant in the room: air pollution:

In findings which have startled scientists, new data shows car pollution is killing thousands of New Zealanders each year and costing the country billions of dollars.

[...]

It found 3300 people were dying yearly because of air pollution, and it was mostly because of cars.

That meant as a whole, 10 percent of the people who died each year in the country were dying because of air pollution.

Exposure was also sending more than 13,000 people to hospital for respiratory and cardiac illnesses and giving the same number of children asthma.

The social cost of these health impacts was estimated to be $15.6 billion.

And that's per year. To give an idea of this, the total cost of all road transport greenhouse gas emissions (13.18 million tons at $150/ton) is just under $2 billion a year. So air pollution is almost eight times larger - and apparently not factored into our calculations at all.

This should have a massive effect on all future benefit-cost analyses of future transport spending. The good news is that the sorts of solutions which eliminate transport carbon emissions - mode shift, public transport, and switching to EVs - also eliminate air pollution: you don't get nitrogen dioxide from inefficient combustion when you don't burn anything. So it pushes in the same direction we want to go in, only much, much faster. How fast? Well, if we assume that every one of the 4.4 million vehicles in Aotearoa is a large car (they're not), costing $40,000 to replace (the average in 2021), then full replacement would cost $176 billion. Factoring in the cost of air pollution means it pays for itself in twelve years. Which is about the sort of timescale we need to change in to avoid climate disaster.