Drowsy drivers don’t attract as much public opprobrium as drunk or distracted drivers, but maybe they should.

According to a newly released survey of 2,000 motorists by the AAA Foundation for Traffic Safety, 41 percent of drivers admitted they had “fallen asleep or nodded off” while driving at least once. Eleven percent said they had done so within the past year, and four percent said they had fallen asleep behind the wheel in the previous month.

Moreover, one in four motorists admitted they had driven when they were “so sleepy that they had a hard time keeping their eyes open” within the past month.

Given the mushy nature of the data, it’s hard to make accurate estimates of the number of accidents caused by fatigue. After all, haven’t all of us nodded off at one time or another?

Nevertheless, AAA’s researchers concluded that as many as 16 percent of all fatal crashes involved a drowsy motorist – a much higher estimate than earlier studies which attributed less than four percent of fatal accidents to fatigue.

“Researchers have always thought that drowsy driving is under-reported, and that’s what this study found,” said AAA spokesman Dan Bleier. “We know that it’s a problem, and people need to pay attention to it.”

There were some other interesting findings: Men are much more likely than women to drive while fatigued, and motorists between the ages of 16 and 24 also are high risks. Though most of us would associate drowsy driving with long overnight trips, a substantial number of incidents occurred during short trips in the afternoon.

Ten Dead, Five Hurt

If AAA is correct, drowsy motorists are almost as dangerous as drunk drivers, who caused one third of all fatal accidents last year.

A particularly horrific example of drowsy driving surfaced in September, when the National Transportation Safety Board released its investigation of a crash that killed 10 people on a highway near Miami, Oklahoma.

On the afternoon of June 26, 2009, a Ford Focus headed east on Interstate 44 sideswiped a tractor-trailer parked on the right shoulder. The driver lost control, hit the concrete median and came to a halt in the left lane. No injuries so far, but the fender bender tied up traffic.

Six minutes later, a 76-year-old trucker driving a Volvo tractor-trailer failed to notice that the cars ahead of him had stopped. He never slowed and he never swerved. Going 69 mph, his truck slammed into the rear of a Land Rover, rode over a Hyundai Sonata and a Kia Spectra, then smashed into a Ford Windstar minivan. The out-of-control rig shoved the Windstar into a livestock trailer towed by a Ford pickup, which in turn hit a Chevy Tahoe. The final toll: 10 dead, and five injured.

Investigators concluded that the truck driver suffered from acute fatigue.

The report also recommended that all new commercial trucks be equipped with collision warning systems. Such a device “would have significantly reduced the likelihood that this accident could ever have happened,” said NTSB Chairwoman Deborah Hersman.

One might logically ask whether drowsiness detection systems should also be mandated for vehicles. Wouldn’t it make sense to detect dangerous behavior before an accident is imminent?

“Time For A Rest?”

Indeed, several automakers have tinkered with such devices. For example, Mercedes-Benz has developed a system called Attention Assist, which is standard equipment on E-Class, CL-Class and some S-Class sedans.

If the system’s sensor detects erratic steering, an audible warning sounds and the instrument panel flashes the message: “Time for a rest?”  Such initiatives “give the driver feedback to wake up and get off the road safely,” says Justin McMaull, AAA’s director of state relations. 

But somehow, it doesn’t seem plausible to expect exhausted motorists will pull over simply because the dashboard is flashing an icon of a coffee cup. Behaviorists might argue that motorists won’t change their behavior unless they can be punished for it.

That approach is getting a test in New Jersey, which passed a law banning drowsy driving in 2003. Jersey motorists involved in a traffic accident are considered to be “knowingly fatigued” if they’ve been awake more than 24 hours. Maximum penalties include a 10-year prison sentence and a $100,000 fine.

But drowsy motorists are harder to identify than drunk drivers. You can’t give a motorist a Breathalyzer test for fatigue, McMaull notes. It’s hard to prove in court, which may be why no other state has followed New Jersey’s lead.

Still, McMaull says the law isn’t useless. “The idea is to send a message to motorists,” he says. “And prosecutors can use it as a legal tool after a serious crash.”

Is the problem getting worse? It isn’t clear. This is AAA’s first survey of drowsy drivers -- perhaps subsequent studies will reveal a trend.

In the meantime, motorists should use some common sense:

1.    If you’re on a long trip, pull over for a break every couple of hours.
2.    Have some coffee; it will perk you up for awhile.
3.    A companion in the car can keep you awake and share driving chores.
4.    Break up long trips with an overnight motel stop. Don’t attempt an all-night drive.
5.    Stay away from alcohol. A fatigued motorist on booze is double trouble.