Drivers who fail to get seven hours of sleep a night are almost twice as likely to be involved in an accident, according to research by the American Automobile Association.
The researchers found that missing between one and two hours of sleep makes an accident twice as likely, and that missing two to three hours of sleep quadruples the risk. This is the same crash risk associated with driving over the legal alcohol limit.
The report is based on an analysis of 7,234 drivers involved in 4,571 crashes. All sample cases involved at least one vehicle being towed from the scene and resulted in emergency medical services being dispatched. The report also reveals that a lack of sleep is a factor in one in five fatal crashes on US roads.
Dr David Yang, the AAA Foundation for Traffic Safety’s executive director, said: ’You cannot miss sleep and still expect to be able to safely function behind the wheel. Our new research shows that a driver who has slept for less than five hours has a crash risk comparable to someone driving drunk.’
Jake Nelson, the AAA’s director of Traffic Safety Advocacy and Research, said: ‘Managing a healthy work-life balance can be difficult and far too often we sacrifice our sleep as a result. Failing to maintain a healthy sleep schedule could mean putting yourself or others on the road at risk.’
There are several strict regulations concerning driving and certain medical conditions — epilepsy and obstructive sleep apnoea, for example — but generalised tiredness as a risk factor is far more nebulous and vague as to its impact on road safety.
This American study suggests that missing as little as one to two hours of sleep could double the risk of having a serious crash. It sets a rather arbitrary seven hours of sleep a night as the usual requirement but its key finding was that the crash risk for sleep-deprived drivers increases steadily the less sleep we get, with a risk of over 11 times in drivers getting less than four hours of sleep compared with those sleeping seven hours or more each night.
This is not a new finding — we have known for a long time of the potential risks of driving when tired — but it does help to remind us not to drive when tired if at all possible, especially with the festive season coming up.
Research score: 3/5