According to the Centers for Disease Control and Prevention (CDC), drowsy driving is the dangerous combination of driving when sleepy. Drowsiness can make a person less able to pay attention to the road, lead to slow reaction time, and affect the ability to make good decisions.
According to the National Highway Traffic Safety Administration (NHTSA), drowsy-driving crashes:
- occur most frequently between midnight and 6 a.m. or in the late afternoon
- often involve a single driver with no passengers
- frequently happen on rural roads or highways.
The chart below shows that in 2021, 2.2 percent of fatal crashes were caused by drivers who were drowsy, asleep, fatigued, ill, or blacked out.
| Behavior |
Number (1) |
Percent |
| Driving too fast for conditions or in excess of posted limit or racing |
10,295 |
19.1% |
| Under the influence of alcohol, drugs, or medication |
6,246 |
11.6 |
| Operating vehicle in a careless manner |
3,958 |
7.3 |
| Failure to yield right of way |
3,663 |
6.8 |
| Failure to keep in proper lane |
3,337 |
6.2 |
| Distracted (phone, talking, eating, object, etc.) |
2,968 |
5.5 |
| Operating vehicle in erratic, reckless or negligent manner |
2,356 |
4.4 |
| Failure to obey traffic signs, signals, or officer |
2,250 |
4.2 |
| Overcorrecting/oversteering |
1,744 |
3.2 |
| Vision obscured (rain, snow, glare, lights, building, trees, etc.) |
1,533 |
2.8 |
| Drowsy, asleep, fatigued, ill, or blacked out |
1,165 |
2.2 |
| Swerving or avoiding due to wind, slippery surface, etc. |
1,138 |
2.1 |
| Driving wrong way on one-way traffic or wrong side of road |
1,060 |
2 |
| Making improper turn |
368 |
0.7 |
| Other factors |
5,921 |
11 |
| None reported |
8,659 |
16.1 |
| Unknown |
16,885 |
31.3 |
| Total drivers (2) |
53,890 |
100.0% |
(1) Number of drivers and motorcycle operators.
(2) The sum of the numbers and percentages is greater than total drivers as more than one factor may be present for the same driver.
Source: U.S. Department of Transportation, National Highway Traffic Safety Administration.
Additional resources
Centers for Disease Control and Prevention, Drowsy Driving: Asleep at the Wheel.
National Safety Council, Drivers are Falling Asleep Behind the Wheel.
