Forty-one percent of motorists reported having fallen asleep while driving passenger vehicles, according to AAA survey released this month.

The AAA Foundation for Traffic Safety survey of 2,000 U.S. drivers yielded very similar results to a 2003 National Highway Traffic Safety Administration drowsy driving report, the association said. It also noted a new NHTSA data analysis estimate that indicates a drowsy driver is involved in one in 14 crashes where a passenger vehicle was towed.

Fifty-nine percent of those who reported having fallen asleep while driving in the past year said this occurred after driving less than an hour. One in five reported they had been driving for three hours or longer when they went to asleep.

Still, 85 percent of respondents said it was completely unacceptable to drive if so tired they are having trouble keeping their eyes open.

The survey also indicated:

• One in ten survey participants reported falling asleep at the wheel in the past year.