Could driverless cars really cut road accidents by 95%?

A driverless Hyundai Genesis. Image: IoME.

A new report from the Institute of Mechanical Engineers (IoME) is leading on a striking statistic. It claims that the introduction of driverless cars "could prevent up to 95 per cent of all traffic accidents". 

This sounds pretty great, especially since 1,755 people died in road accidents in 2014 in the UK alone. If we apply the IoME's metric, we can guess that a fully driverless road network would have saved 1,667 lives that year.

So if that's true, then why aren't we going full speed ahead (sorry) with autonomous vehicles?  

Unfortunately, when you look at the report more closely, it becomes clear that the claim isn't quite what it seems. It's drawn from the fact that the National Highway Traffic Safety association estimates that 95 per cent of accidents are down to driver error. Ergo, the headline writer must have thought, removing drivers from the equation would surely cut out those accidents completely. 

Once we live in a world of 100 per cent driverless vehicles, it is possible this could be the case. However, in that environment it seems likely that accidents would come from other directions: technology failure, bad weather, or loss of signal, say. While unpredictable situations may be rarer on an autonomous road network, the cars may still be less well equipped to deal with them than a human driver would be.

The bigger issue, though, is that we won't reach a fully autonomous network any time soon. First, we have to get through an era of mixed driverless and non-driverless cars on the road. Especially at the beginning, drivers might be nervous about autonomous vehicles, which could actually increase driver error, not reduce it. 

This point has also been missed by those who point out that, in all the accidents involving driverless cars during testing, the cars with drivers have almost always been at fault. No car exists in a vacuum: the driverless vehicle still wasn't able to prevent the accident, and it's hard to know if the non-human decisions of the vehicle may have contributed in some small way. 

In its report, the IoME calls for new regulatory regimes, training for owners of driverless cars and new signage and markings to prepare for the new cars. But it's the interaction of driver and driverless that urgently needs exploring if we're planning to mix the two in the very near future. 


CityMetric is now City Monitor! Come see us at our new home

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CityMetric is now City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications from New Statesman Media Group. Our new site is now live in beta, so please visit us there going forward. Here’s what CityMetric readers should know about this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

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As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

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Sommer Mathis is editor-in-chief of City Monitor.