Drowsy Driving

Being awake for 18 hours affects your driving about as much as a blood alcohol level of 0.05%, and 24 hours awake is similar to 0.10%, above the legal limit. Drowsy drivers can drift into micro-sleeps lasting a few seconds without knowing it. Drowsy crashes often happen at high speed with no braking.

• All drivers
• Shift workers
• Teen drivers

Warning signs

• Frequent yawning or blinking
• Trouble remembering the last few miles
• Missing your exit
• Drifting from your lane or hitting a rumble strip
• Heavy eyelids or nodding head

If you notice any of these, pull over somewhere safe. They mean you’re already impaired.

Who is most at risk

• Shift workers and people working long or night shifts. See Night Work.
• Teen and young drivers.
• Commercial drivers. See Driver Fatigue & Sleep Apnea.
• People with untreated sleep disorders like sleep apnea.
• People taking medicines that cause drowsiness.
• Anyone driving between midnight and 6 a.m., or in the mid-afternoon dip.

Tricks that don’t work

Turning up the radio, opening the window, chewing gum or slapping your face don’t restore alertness. They might keep you awake a few extra minutes, but your reactions stay slow.

What works

• Get 7 to 9 hours of sleep before a long drive.
• Take a break every 2 hours or 100 miles on long trips.
• If you’re drowsy, pull into a safe place and take a 20-minute nap.
• Caffeine can help for a short time; it takes about 30 minutes to kick in. A coffee followed by a short nap works better than either alone.
• Share the driving on long trips.
• After a long or overnight shift, consider getting a ride, taking transit or resting before driving home.

Last updated: October 1, 2026