According to the National Sleep Foundation’s 2005 Sleep in America poll, 60% of adult drivers, roughly 168 million people, said they drove a vehicle while feeling drowsy in 2004.

The poll also found that more than 103 million people have actually fallen asleep at the wheel.

Jeremy Lyon with Brentwood Driver Training says adults between the ages of 18 and 29 are most likely to drive drowsy, but that the number of crashes involving sleepy young parents are also on the rise.

Lyon recommended drivers recognize when they’re tired and take frequent breaks. Stopping and sitting in the car isn’t enough, Lyon said. Standing and walking around is the best for reviving the body before getting back behind the wheel.

He also stated that driving without sleeping within 24 hours is the equivalent to driving intoxicated over the legal limit.