How much does poor sleep increase your chances of a car crash?

Best make sure you get a good night's kip before setting out on your next road trip.

Image credit: Getty

Published: April 18, 2024 at 5:00 pm

Drowsy driving, like drunk driving, can be dangerous because poor sleep affects hand-eye coordination, vigilance and reaction times. 

Accurately measuring the effect of a poor night’s sleep on road safety is difficult, however. Unlike blood alcohol, tiredness is difficult to quantify. 

The US National Highway Traffic Safety Administration attributed 1.6 per cent of road deaths (684 fatalities) in 2021 to drowsy driving, though it’s been suggested the true figure could be much higher.


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A study by the American Automobile Association Foundation for Traffic Safety estimated that getting between five and six hours of sleep almost doubled the risk of a crash, while those who slept for four to five hours had more than four times the crash rate.

This article is an answer to the question (asked by Lester Herbert, via email) 'How is your driving affected after a night of insomnia?'

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