Before you head out on the road for 4th of July, make sure you're well rested.
More than 7,000 fatal car crashes might involve drowsy driving each year -- according to a new report from the Centers for Disease Control and Prevention.
Researchers looked at survey data filled out by more than 90.000 Americans, in particular questions about sleep patterns and driving habits.
They found four percent had fallen asleep while driving within the past month.
Drowsy driving poses its own risks, with slower reaction times and less attention to surroundings.
Researchers found men, young drivers, binge drinkers and people who don't wear seatbelts were most likely to drive while sleepy.
Researchers say the best way to prevent drowsy driving is to get enough sleep and avoid alcohol before hitting the road.
Tactics like turning the radio up, rolling the windows down and turning up the air conditioner don't work.