Driving drowsy is a major factor in traffic accidents and deaths in the United States, federal health officials reported Thursday.
Federal statistics state that 2.5 percent of fatal motor vehicle crashes and 2 percent of crashes with non-fatal injuries involve drowsy driving.
According to the report by the U.S. Centers for Disease Control and Prevention, more than 4 percent of drivers quizzed said they had driven while drowsy in the month before the survey.
But some studies have estimated that 15 to 33 percent of fatal crashes may involve sleepy drivers.
"One out of 25 people reported falling asleep while driving in the past month," said CDC epidemiologist Anne Wheaton, the report's lead author. "If you think of how many cars you see every day, one out of 25 -- that's a pretty big number."
And those numbers may underestimate the scope of the problem, Wheaton said.
"These were people who realized they had fallen asleep while they were driving," she said. "If you fall asleep for even a moment you may not realize it -- so that's not even taking those people into account."
The report was published in the Jan. 4 issue of the CDC's Morbidity and Mortality Weekly Report.
