Why are American roads so dangerous?

I have good news and bad news about America’s roads. The good news is the number of people killed in traffic collisions fell by almost 4 per cent in 2023. The bad news is the mortality rate on US roads is still 25 per cent up on a decade earlier, and three times the rate of the average developed country.

Most of the explanations commonly put forward for why US roads remain so deadly focus on broad structural factors such as vehicle size or time spent on the road, but a review of the evidence suggests this may be mistaken. Last year’s improvement is a case in point. Two reasons often cited as key causes of poor US performance both worsened: the total number of miles driven by Americans increased, and US cars continued to grow larger. Yet fatal collisions still declined.

Car-centrism in the US is clearly part of its road safety problem — it’s about culture more than geography. So committed are Americans to their cars that 63 per cent of people choose to drive for trips of less than a mile, compared with 16 per cent in the UK. But even after adjusting for distance driven, US fatality rates remain double the rich-world average. The main reasons American roads are so unsafe stem from how they drive, not how much.

On vehicle size, there is a wealth of evidence that larger cars are more deadly to pedestrians, but the contribution of America’s bloated fleet to its fatality rates turns out to be modest. US pedestrian deaths would be roughly 10 per cent lower if all SUVs and pick-up trucks were replaced with standard-sized cars, according to a study by Justin Tyndall, assistant professor of economics at the University of Hawaii.

Adding to the evidence that this is not a dominant factor, car sizes in Canada, Australia and New Zealand have traced similar paths to the US without resulting in a spike in fatalities.

Another theory is that the rise of homelessness in the US may be pushing pedestrian deaths higher. A recent study found that there had indeed been a marked rise in traffic-related deaths among the homeless, but this, too, can only explain a small portion of the overall rise.

Instead, an underrated factor seems to be not American cars but American drivers.

In an eye-opening analysis last year, Emily Badger, Ben Blatt and Josh Katz of The New York Times revealed that the rise in US road deaths was driven almost exclusively by pedestrian fatalities happening at dusk under fading light when drivers are most likely to be using their phones. A theory emerged that the proliferation of smartphones in a population who, unlike their European counterparts, almost exclusively drive cars with automatic transmission gives them a false sense of security about how dangerous it is to multitask at the wheel.

Yet this idea only half works. Using phones at the wheel is a big problem in the US, according to data from Cambridge Mobile Telematics. But just across the border, Canadians, who also drive automatics, spend less than half as much time using their devices while driving. The determining factor seems to be different attitudes to safety, with Americans twice as likely as Canadians or Europeans to say they find it acceptable to use a phone while driving.

The same pattern shows up in other behaviours. Americans are much less likely to wear seat belts than most Europeans and also have higher rates of drink-driving.

Given that studies find a lack of seat belts, alcohol and distracted driving all increase either the likelihood or lethality of a collision by a greater amount than vehicle size or shape — and that American drivers are more exceptional in these behaviours than in their car size — these factors may be the determining ones.

To be clear, driver habits don’t form in a vacuum, and they can and must change. As transport expert David Zipper points out, everything from the design of streets, to investment in public transport, to stricter — and enforced — laws on drinking, speeding, mobile phone usage and seatbelt-wearing has been proved to shape behaviour. This also shows up in the wide variation in road death trends between US states with more and less strict road safety laws.

Taking all the evidence together, America’s dire record on the roads is neither the result of happenstance nor industry-wide trends. If the US is to achieve developed-country levels of road safety, America and Americans need to change direction.

john.burn-murdoch@ft.com, @jburnmurdoch

Letters in response to this column:

US drug laws put road users on collision course / From Lis Rhodes, Concord, MA, US

Why the nanny state is partly to blame for US road carnage / From George P Csicsery, Zala Films, Oakland, CA, US