Drivers who sleep less than seven hours a night significantly raise their risk of getting in a crash, and motorists who miss two to three hours of sleep in a 24-hour period are about as dangerous as those who drive while drunk.
Those are two of the findings of a new study out Tuesday from the AAA Foundation for Traffic Safety looking at the dangers associated with drowsy driving, which is a factor in more than one in five motor vehicle crashes each year.
About 35 percent of drivers in the United States get less than the recommended seven hours a sleep, the Centers for Disease Control and Prevention says. Those cut an hour of sleep are 1.3 times more likely to crash and those who get only five hours of sleep double their risk. At less than five hours, motorists quadrupled their risk of a crash compared to drivers getting the recommended seven hours of sleep, the study
Sleeping four hours or less was associated with having a blood-alcohol content of .12 to .15 percent, the study found. The National Sleep Foundation concluded that individuals who have slept 2 hours or less within a 24-hour period are not fit to operate a vehicle.
“You cannot miss sleep and still expect to be able to safely function behind the wheel,” said David Yang, executive director for the AAA Foundation for Traffic Safety. “Our new research shows that a driver who has slept for less than five hours has a crash risk comparable to someone driving drunk.”
The study analyzed more than 4,571 crashes between 2005 and 2007 in which emergency medical services were required and at least one vehicle towed from the scene due to damage.
Surveys of drivers found that a third admitted that in past month they drove at least one time when they were so tired they had a hard time keeping their eyes open.
“Managing a healthy work-life balance can be difficult and far too often we sacrifice our sleep as a result,” said Amy Stracke, managing director of Traffic Safety at AAA – The Auto Club Group. “Failing to maintain a healthy sleep schedule could mean putting yourself or others on the road at risk.”
Symptoms of drowsy driving can include having trouble keeping eyes open, drifting from lanes or not remembering the last few miles driven. However, more than half of drivers involved in fatigue-related crashes experienced no symptoms before falling asleep behind the wheel, the foundation said.
Along with getting seven hours of sleep, motorists making long trips should travel at times when they are normally awake, take a break every two hours or 100 miles, avoid heavy foods and travel with an alert passenger to share driving chores with.