Driving Dangerously by Driving Drowsy

From the WebMD Archives

May 2, 2000 -- Thanks to all of the hard work by Mothers Against Drunk Driving (MADD) and others, most of us are aware of the hazards of drunken driving. However, few of us are aware that driving while drowsy can be just as -- if not more -- dangerous. But individual efforts and statewide awareness campaigns are helping to educate drivers about the importance of adequate sleep and the dangers of drowsy driving.

About half of U.S. adults admit to driving while drowsy, and 17% have actually fallen asleep at the wheel, according to a recent poll by the National Sleep Foundation. The National Highway Traffic Safety Administration estimates that at least 100,000 crashes, 71,000 injuries and 1,500 deaths each year in this country are the result of a driver falling asleep at the wheel. And that's not all. About one million crashes each year occur as a result of driver inattention or lapses of attention, and sleeplessness increases the risk of such lapses. Still, experts tell WebMD that drowsy driving accidents may even be underreported because police officers do not routinely ask about sleepiness at crash sites.


Drowsy drivers are more likely to crash than well-rested drivers because they have slower reaction times; impaired judgment and vision; and pay less attention to important signs, road changes, and actions of other drivers.

Four populations are especially hard hit by drowsy driving, Thomas Roth, PhD, head of the division of sleep medicine at Henry Ford Hospital in Detroit, tells WebMD. "Drowsy driving is a significant problem in a variety of groups -- young people, especially males age 18 to 25, because they don't tend to get enough sleep; shift workers; people with untreated sleep disorders, such as sleep apnea and narcolepsy; and commercial drivers, because they are on the road so much," Roth says.

People with sleep apnea -- a serious sleep disorder marked by snoring, pauses in breathing during sleep, and struggling to breathe during sleep -- are three to seven times more likely to crash as people without the disorder. Narcolepsy is characterized by excessive and overwhelming drowsiness. People with the condition tend to fall asleep at inappropriate times and places, including behind the wheel.


"Your safety and that of others on the road is at risk when you drive while drowsy," says Pat Britz, education and research manager at the National Sleep Foundation in Washington, D.C. "If you are going to drive, make sure you get eight hours of sleep the night before or take a nap on the day you depart," she tells WebMD. Studies have shown that only one-third of Americans get their recommended eight hours of sleep each night.

For long trips, Britz says, drivers should schedule stops or rests every two hours and alternate drivers throughout the trip. Avoid alcohol or sedating medications when driving. "Sleepiness can accentuate the effects of alcohol and vice versa," she says. Sedating medications include certain antidepressants, anti-anxiety medications, and some antihistamines.

"Two cups of coffee can increase short-term alertness, but it's no substitute for proper sleep," she says. Remember that it takes about 30 minutes for the effects of caffeine to enter the bloodstream.


Recognizing warning signs of sleepiness among drivers also is important, Britz tells WebMD. They include difficulty focusing or keeping your eyes open; trouble keeping your head up; yawning repeatedly; wandering, disconnected thoughts or day dreaming; feeling restless or irritable; trouble remembering the last few miles driven; drifting from your lane or hitting a rumble strip; tailgating; and missing traffic signs or exits, she says.

As more attention is paid to the dangers of drowsy driving, some states are including information about the dangers of it in their driver education programs. Other preventive measures on the horizon include focusing a public awareness campaign on the use of shoulder rumble strips as an effective countermeasure to drowsy driving.

Rumble strips are raised or grooved patterns on the shoulders of highways to alert drivers that they have veered off the road. When tires pass over them, they produce a sudden rumbling sound and cause the vehicle to vibrate. Some research suggests that rumble strips can decrease risk of crashes by as much as 70%. The public awareness campaign will focus on alerting drivers who veer onto rumble strips that they should take it as a warning that they are too tired to drive.

For more information on drowsy driving, contact the National Sleep Foundation.

Vital Information:

  • A recent poll by the National Sleep Foundation found that half of U.S. adults admit to driving drowsy and nearly a fifth have fallen asleep at the wheel.
  • Safety officials attribute at least 100,000 crashes, 71,000 injuries and 1,500 deaths each year to drivers falling asleep. There may be a larger toll due to sleep, but it's not usually investigated at crash sites.
  • Those particularly at risk of being sleepy drivers are young people (especially males) between ages 18 and 25, shift workers, people with sleep disorders, and those who drive professionally.
  • Experts recommend people recognize when they are tired and not drive. Before long drives, people should get enough sleep, schedule rest stops every two hours, and change drivers frequently. Also, look out for medicines that cause drowsiness.
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