Driving when you haven’t had enough sleep can cause you to be a drowsy driver, which can be just as bad as drunk driving, suggests a new study. The study found that sleeping less hours a night increases your likelihood of being a drowsy driver. And drowsy driving accounts for 15% to 33% of fatal car crashes. Got that? Like drunk driving, drowsy driving kills! And there’s no equivalent of a breathalyzer to determine whether you’re in a healthy state to drive, so you’ll just have to use you head. If you can barely keep your eyes open and you have to drag yourself to the front door, then it’s probably not a good idea to drive. So instead catch a ride with a pal, call a cab or take a power nap if you’re in no hurry.  In the study, compared to people who slept seven hours per night, those who slept six or fewer hours were twice as likely to report drowsy driving and those who slept five or fewer hours a night, were four times as likely.