Plenty of people feel uncomfortable about the idea of driverless cars, and much of this discomfort stems from the safety aspect. Computers can’t be trusted to deal with the high speeds of the open road, especially when human lives are at risk, it’s argued. It turns out you could quite comfortably swap the word “computers” with “humans”, and you’d have a perfectly reasonable sentiment. We’re all pots calling the kettle black.

See related Volvo warns US it’s lagging behind on driverless car laws How do Google’s driverless cars work? Driverless cars: could your next car be driven by a robot? Our frequent human fallibility is confirmed by a new study to come out of Virginia Tech, which has just compiled a large-scale database of 1,600 crash events collected from 3,500 drivers across the United States. There are all kinds of things that can increase the risk of having an accident behind the wheel, and plenty of them come down to common sense, but the sample size means we get an idea of how risky each behaviour is.

“We have known for years that driver-related factors exist in a high percentage of crashes, but this is the first time we have been able to definitively determine – using high-severity, crash-only events that total more than 900 – the extent to which such factors do contribute to crashes,” said Tom Dingus, director of the Transportation Institute at Virginia Tech.

The surprising headline risk is our emotions. People who drive while angry or sad increase their risk of crashing by nearly tenfold. That makes it a far greater risk than using mobile phones or touchscreen menus on in-car computers, which “only” double the risk of being in an accident.

Speeding is worse, though. Going over the speed limit increases the likelihood of a crash by around 13 times – slightly more risky than dialling a number on the phone in your hand, which increases the risk by 12 times. Reaching for an item makes you nine times more likely to crash – unless it’s a phone, at which point it drops to six. Fatigue makes you three times as likely to crash, but bafflingly, applying makeup while driving and tailing other vehicles at an “unsafe” distance didn’t factor in the crash data – although I really wouldn’t recommend either.

What do all these factors have in common? Computers don’t do any of them. In fact, of the 1,600 verified crash incidents (of which 905 were “high-severity” involving injury or property damage), the buck stopped with the driver in 90% of cases. By contrast, last May Google announced that after one million miles worth of roads covered, its driverless cars had been involved in just 11 accidents, which Google was quick to blame on – you guessed it – human error.

Virginia Tech’s report isn’t designed to promote driverless cars, though. In fact, Dingus is more concerned about the possible repercussions for a generation of younger drivers, who are more likely to engage in the high-risk behaviours highlighted. “Our analysis shows that, if we take no steps in the near future to limit the number of distracting activities in a vehicle, those who represent the next generation of drivers will only continue to be at greater risk of a crash.”

If this piece has made you angry or sad about your fellow road users, it’s probably best you don’t get behind the wheel until you’ve calmed down – otherwise, it turns out, you’re just part of the problem.

READ NEXT: How do self-driving cars work?

Images: Sheri and Saad Faruque used under Creative Commons