You’re yawning a lot, and your eyelids are so heavy you’re having trouble keeping them open. You might even have trouble keeping your head up. If you’re at home, it’s probably naptime. If you’re behind the wheel, it’s time to stop driving!

As many as two-third of adult drivers admit to drowsy driving, despite the increased risks of being behind the wheel.  Driver fatigue causes about 100,000 crashes each year, resulting in 1,550 deaths, 71,000 injuries, and $12.5 billion in damages—and these are conservative estimates, according to the National Highway Traffic Safety Administration. Driver fatigue, in fact, was cited as a contributing factor to the recent fatal bus crash on I-95 north of Richmond, killing 4 passengers when the bus overturned.

Sleepiness can impair drivers much like alcohol, causing slower reaction times, vision impairment, lapses in judgment, and delays in processing information. If you’re behind the wheel and experience any of the following warning signs, stop driving, find a safe place to pull over, and address your condition:

• Frequent blinking and/or heavy eyelids
• Difficulty focusing your eyes
• Inability to prevent daydreaming
• Difficulty keeping your head up
• Drifting from your lane, swerving, or hitting rumble strips
• Inability to remember the last few miles driven
• Missing exits or traffic signs
• Repeated yawning
• Feeling restless, irritable, or aggressive