How dangerous is drowsy driving?

According to NHTSA, fatigue slows reaction time, impairs judgment, and can cause “microsleeps”—brief lapses of attention lasting a few seconds, long enough at highway speed to travel the length of a football field with no one watching the road. Studies equate 20 hours awake to roughly the legal alcohol limit.

Who is most at risk?

Commercial truck drivers, shift workers, people with untreated sleep disorders, and anyone driving late at night or on long monotonous trips are at elevated risk. When a commercial driver violates federal hours-of-service rules and causes a fatigue-related crash, both the driver and the trucking company can be liable—see our truck accident page.

How do you prove a driver was drowsy?

Fatigue leaves evidence: no skid marks or braking before impact, a single-vehicle drift, the time of day, the driver’s work and sleep schedule, phone and dashcam data, and for commercial drivers the electronic logging device (ELD) and hours-of-service records. Statements to police at the scene often reveal the driver had been awake too long.

Quick Reference

Frequently Asked Questions

Is drowsy driving illegal in California?

There is no specific ‘drowsy driving’ statute, but a driver who causes a crash because they were too fatigued to drive safely is negligent and can be held liable for the resulting injuries.

How is drowsy driving similar to drunk driving?

Research cited by NHTSA shows that being awake for about 20 hours impairs driving similarly to a 0.08% blood-alcohol concentration—the legal limit. Both slow reaction time and impair judgment.

Can a trucking company be liable for a drowsy driver?

Yes. If a commercial driver violated federal hours-of-service rules or the company pressured unrealistic schedules, both the driver and the carrier can be held responsible for a fatigue-related crash.