4% of United States adults have fallen asleep or dozed off while behind the wheel. Sleepy driving is more common among adults who sleep less than six hours per night, snore, or fall asleep randomly during the day, compared with people who do not. Ways used to stay awake while driving, such as opening the window, turning up the AC and radio, are usually unsuccessful. Warning signs of sleepiness include hitting a rumble strip, drifting from one’s lane, missing exits, yawning or blinking, and trouble remembering driving the last few miles.
CDC, January 2013