1 in 24 Americans Drives Drowsy, CDC Says

One in 24 American drivers has admitted to falling asleep at the wheel in the past month, according to a new report on drowsy driving by the U.S. Centers for Disease Control and Prevention.

The report, based on a survey of nearly 150,000 drivers in 19 states and D.C., suggests sleepiness aggravated by shift work and snoring can be as risky as alcohol, slowing reaction times and impairing decision-making behind the wheel.

"Drivers need to avoid driving while drowsy and learn the warning signs," said study author and CDC epidemiologist Anne Wheaton. She said red flags include yawning, drifting between lanes and missing exits.

"If a driver recognizes the signs, they need to get off road as soon as possible in a safe area until they are able to drive again or change drivers," Wheaton said.

CLICK HERE to see ABC News' Ron Claiborne "microsleep" while driving.

The National Highway Traffic Safety Administration estimates that 2 percent of motor vehicle crashes involve drowsy driving. And drowsy driving crashes are more likely to be fatal, according to Dr. Kingman Strohl, interim division chief of pulmonary, critical care and sleep medicine at UH Case Medical Center in Cleveland, Ohio.

"A typical driver makes about 1,000 decisions a minute," said Strohl, explaining how fatigue can foil attempts to avoid catastrophic collisions. "If a person has not slept for 18 consecutive hours, their impairment on those decision-making tasks is similar to that of someone above the legal alcohol limit."

While rumble strips designed to rouse dozy drivers with a loud buzz and jittering shake and have helped cut crash numbers, Strohl said more needs to be done to educate drivers and about the risks of driving drowsy.

"We get a lot of information in driver training about drunk driving, but we don't have enough emphasis on sleepiness," he said. "Even in general, we don't have enough emphasis on the importance of sleep compared to what we know about nutrition and exercise."

Drowsy driving rates varied across states, from a low of 2.5 percent in Oregon to a high of 6.1 percent in Texas. Men were more likely to drive drowsy, as were younger adults, according to the study.

"Most of us have experienced being sleepy and driving, and I think that's the reason why the prevalence drops with age," said Strohl. "It's scary. And if it happens to you, you don't want to repeat it."

While winding down windows and blasting music may offer temporary relief from fatigue, the only effective treatment for drowsiness is sleep - and a couple cups of coffee, according to Wheaton.

"To prevent drowsy driving, people need to get at least seven hours of sleep," she said, stressing that people who feel they might have a sleep disorder should seek treatment. "And if you're taking a medication that can make you drowsy, pay attention to that label and be aware that it might make you too sleepy to drive."