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Drowsy Driving

Sleepiness can result in crashes any time of the day or night, but three factors are most commonly associated with drowsy-driving crashes.

Drowsy-driving crashes:
     1. Occur most frequently between midnight and 6 a.m., or in the late afternoon. At both times of the day, people experience dips in their circadian rhythm—the human body’s internal clock that regulates sleep;
     2. Often involve only a single driver (and no passengers) running off the road at a high rate of speed with no evidence of braking; and
     3. Frequently occur on rural roads and highways.

Fatigue has costly effects on the safety, health, and quality of life for everyone.

Whether fatigue is caused by sleep restriction due to a new baby waking every couple of hours, a late or long shift at work, hanging out late with friends, or a long and monotonous drive for the holidays – the negative outcomes can be the same. These include impaired cognition and performance, motor vehicle crashes, workplace accidents, and health consequences.

Tackling these issues can be difficult when our values frequently do not align with avoiding drowsy driving. In a 24/7 society, with an emphasis on work, longer commutes, and exponential advancement of technology, many people do not get the sleep they need. Effectively dealing with the drowsy-driving problem requires fundamental changes to societal norms and especially attitudes about drowsy driving.

Drowsy-driving crashes:

  1. Occur most frequently between midnight and 6 a.m., or in the late afternoon. At both times of the day, people experience dips in their circadian rhythm—the human body’s internal clock that regulates sleep;

  2. Often involve only a single driver (and no passengers) running off the road at a high rate of speed with no evidence of braking; and

  3. Frequently occur on rural roads and highways.


NHTSA estimates that in 2021, 684 crash deaths involved drowsy drivers.

Tips on How to Drive Alert:

Getting adequate sleep on a daily basis is the only true way to protect yourself against the risks of driving when you’re drowsy. Experts urge consumers to make it a priority to get seven to eight hours of sleep per night.

Before the start of a long family car trip, get a good night’s sleep, or you could put your entire family and others at risk.
Many teens do not get enough sleep at a stage in life when their biological need for sleep increases, which makes them vulnerable to the risk of drowsy-driving crashes, especially on longer trips. Advise your teens to delay driving until they’re well-rested.

Avoid drinking any alcohol before driving. Consumption of alcohol interacts with sleepiness to increase drowsiness and impairment.

Always check your prescription and over-the-counter medication labels to see if drowsiness could result from their use.
If you take medications that could cause drowsiness as a side effect, use public transportation when possible.
If you drive, avoid driving during the peak sleepiness periods (midnight – 6 a.m. and late afternoon). If you must drive during the peak sleepiness periods, stay vigilant for signs of drowsiness, such as crossing over roadway lines or hitting a rumble strip, especially if you’re driving alone.

Drinking coffee or energy drinks alone is not always enough. They might help you feel more alert, but the effects last only a short time, and you might not be as alert as you think you are. If you drink coffee and are seriously sleep-deprived, you still may have “micro sleeps” or brief losses of consciousness that can last for four or five seconds. This means that at 55 miles per hour, you’ve traveled more than 100 yards down the road while asleep. That’s plenty of time to cause a crash.


If you start to get sleepy while you’re driving, drink one to two cups of coffee and pull over for a short 20-minute nap in a safe place, such as a lighted, designated rest stop. This has been shown to increase alertness in scientific studies, but only for short time periods.

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