Study: Drowsy driving almost as dangerous as driving drunk

A new study suggests drowsy drivers understand the risk but sleep deprivation won't keep them off the road.

The AAA Foundation for Traffic Safety analyzed information from more than 7,200 drivers involved in 4,500 crashes. According to the foundation, 97 percent of drivers viewed drowsy driving as "completely unacceptable behavior that is a serious threat to their safety."

Despite awareness, the foundation reported, "Nearly one in three [drivers] admit that at least once in the past month they drove when they were so tired they had a hard time keeping their eyes open."

The Center for Disease Control and Prevention recommends seven hours of sleep a day. An estimated 35 percent of drivers receive fewer than the recommended hours of sleep.  Crash risks increased with each lost hour:

AAA Foundation for Traffic Safety findings:
Six to Seven Hours of Sleep: 1.3 times the crash risk
Five to Six Hours of Sleep: 1.9 times the crash risk
Four to Five Hours of Sleep: 4.3 times the crash risk
Less than four Hours of Sleep: 11.5 times the crash risk

"You cannot miss sleep and still expect to be able to safely function behind the wheel said Dr. David Yang, Executive Director for the AAA Foundation for Traffic Safety. " Our new research shows that a driver who has slept for less than five hours has a crash risk comparable to someone driving drunk."

AAA urges drivers to make sure getting adequate sleep factors into their daily lives.