Recent research from the National Sleep Foundation shows that 60 percent of people have driven while tired in the past year. Being awake for 24 hours impairs driving as much as having a blood alcohol level of 0.10%—more than enough to score you a D.U.I. If you haven’t gotten your beauty sleep (6.5 to 8 hours nightly!), but you still have to get behind the wheel, try this: Drink something caffeinated, and while you’re waiting for it to kick in, take a 15- to 20-minute nap.