KNOXVILLE, Tenn. (WVLT/AP) — This could give you nightmares: 1 in 24 U.S. adults say they recently fell asleep while driving.
And health officials behind the study think the number is probably higher. That's because some people don't realize it when they nod off for a second or two behind the wheel.
"If I'm on the road, I'd be a little worried about the other drivers," said the study's lead author, Anne Wheaton of the Centers for Disease Control and Prevention.
In the CDC study released Thursday, about 4 percent of U.S. adults said they nodded off or fell asleep at least once while driving in the previous month. Some earlier studies reached a similar conclusion, but the CDC telephone survey of 147,000 adults was far larger. It was conducted in 19 states and the District of Columbia in 2009 and 2010.
"Most people don't realize how sleepy they are. When you're drowsy. That's asleep," said Dr. Roseanne Barker. "A lot of times people think they're just not paying attention or they were listening ot the radio... they may sense that somehow they were distracted, but in fact they'd fallen asleep."
Barker runs Knoxville's Barker Sleep Institute. She says patients with sleep disorders complain about difficulty focusing during the day due to a lack of sleep.
The government estimates that about 3 percent of fatal traffic crashes involve drowsy drivers, but other estimates have put that number as high as 33 percent.
Warning signs of drowsy driving: Feeling very tired, not remembering the last mile or two, or drifting onto rumble strips on the side of the road. That signals a driver should get off the road and rest, Wheaton said.
Even a brief moment nodding off can be extremely dangerous, she noted. At 60 mph, a single second translates to speeding along for 88 feet — the length of two school buses.
To prevent drowsy driving, health officials recommend getting 7 to 9 hours of sleep each night, treating any sleep disorders and not drinking alcohol before getting behind the wheel.