Here’s a sobering finding that underscores the importance of getting enough sleep. A report, from the US “AAA” Foundation for Traffic Safety, finds that missing just an hour or two of shut-eye nearly doubles your chances of a car crash the next day. And getting behind the wheel after getting only four to five hours of sleep quadruples that risk. That’s comparable to driving with a blood alcohol level that is considered legally drunk. Researchers studies 4,600 serious police reported crashes. They found sleep deprived driver’s crash risk increased steadily with fewer hours of sleep, compared with drivers who got seven or more. Drivers whose mistakes contributed to crashes were more likely to report having slept less than usual in the 24 hours before the crash. Drivers operating on four or fewer hours of sleep are a whopping eleven and a half times more likely to be involved in a crash than well rested drivers. The researchers say this is the first study to quantify the relationship between lack of sleep and the risk of collision and they hope it will inspire authorities to take the risk of sleep impaired driving more seriously.