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Friday, April 06, 2007
The Dangers of Drowsy Driving
Drowsy drivers are just as dangerous as drunk drivers, and maybe even more dangerous because they don't realize they are impaired. The fact is that nearly 20 percent of all severe car-accident injuries are associated with driver sleepiness, says a study by the Institute of Medicine.
The human body has two drowsy periods. The first is between midnight and 6 a.m. The second is early- to mid-afternoon. Most people attribute afternoon sleepiness to what or how much they ate for lunch, but in fact the cause is really our biological clocks.
"Before you doze, what becomes impaired is your judgment and your insight," says Mark Mahowald, MD, director of the Minnesota Regional Sleep Disorders Center and professor of neurology at the Medical School at the University of Minnesota. "So what happens to people as they get sleepy is they think, Well, I just have a little way to go, and I'll be able to make it. They don't appreciate the fact that if they think they're sleepy at all, they shouldn't be driving."
The National Highway Traffic Safety Administration (NHTSA) warns that microsleep, which is an involuntary intrusion of sleep or near sleep, can thwart the best efforts to remain awake. The NHTSA explains in its study "Drowsy Driving and Automobile Crashes," 'Often, people use physical activity and dietary stimulants to cope with sleep loss, masking their level of sleepiness. However, when they sit still, perform repetitive tasks (such as driving long distances), get bored or let down their coping defenses, sleep comes quickly.'
At any given time, some 70 million Americans are operating on inadequate sleep, according to the National Sleep Foundation. In a 2005 poll, the NSF discovered that 60 percent of adult drivers say they have driven a vehicle while drowsy in the past year; 37 percent report dozing off while driving at least once in the past year.
"Our 300-year-old Puritan work ethic is running smack into this 24/7 society," says Darrel Drobnich, NSF senior director of Government and Transportation Affairs. "The thing people cut back on is sleep. That's a block of time they have control over. But people need to understand that sleep represents a third of our lives and has a tremendous impact on how we live, think and function during the other two-thirds."
Most people believe that they're more productive when they sleep less, but the fact is that we're actually much more effective when we're rested. Our alertness and mental performance is sustained by getting enough sleep.
Seven to nine hours of sleep a night are needed by most adults to perform at their best, while adolescents need up to nine and a half hours. A University of Pennsylvania School of Medicine report stated that subjects whose sleep was limited to four to six hours per night for two weeks had reduced mental performance when compared to those who hadn't slept for up to two days. What's more, the sleep-restricted subjects reported feeling only slightly sleepy when their performance was at its worst.
Fatigue affects everyone, but these people are at higher risk for fatigue-related crashes:
- People who work long hours. Your risk is increased by 40 percent if you work over 60 hours a week.
- People who work in shifts. Because the sleep-wake cycle is dictated by dark and light, the human body never fully adjusts to shift work. Night-shift workers are likely to get less sleep than those who work 9 to 5 and are more susceptible to succumbing to sleep while driving home from work.
- Young people. Drivers under the age of 30 represent only about one-fourth of licensed drivers but are responsible for almost two-thirds of drowsy-driving accidents. Only 20 percent of adolescents, who are the nation's least experienced drivers, get the optimal amount of sleep on school nights.
- Men. Even though both genders are equally sleep-deprived, males are responsible for roughly three out of four drowsy-driving crashes.
- People suffering from sleep disorders. Nearly 40 million Americans experience sleep disorders such as sleep apnea, restless legs syndrome and insomnia. Sleep disorders can increase your crash risk up to seven times if they are not treated.
- Drowsy driving contributed to 22 to 24 percent of the crashes and almost-crashes.
- Some drivers didn’t realize they had fallen asleep at the wheel until researchers informed them.
Jeff Nigvur, a State Trooper with the Utah Highway Patrol, says he sees many drivers impaired by fatigue. "We're kind of a travel-through state. We typically see people take a 15-hour trip in one shot, overnight," Nigvur said. A typical scenario is one parent drives while the rest of the family sleeps, often without seat belts on. If the driver falls asleep, drifts, awakes, overcorrects and rolls the car, the outcome could be deadly. "We usually see multiple ejections out of the vehicle and get people pretty seriously injured as well as some who are killed," Nigvur said. Small changes on perilous roads can have a big impact. The New York State Police assesses that 35 percent of all deadly crashes along the New York State Thruway are caused by a driver falling asleep at the wheel. After continuous shoulder rumble strips were put in place, accidents caused by drivers falling asleep on the thruway were cut down by 83 percent.
There are now high-end cars that offer features created to warn distracted and drowsy drivers. The AutoVue Lane Departure Warning (LDW) system is comprised of a camera and on-board computer that is attached to the windshield or dashboard or overhead, and triggers an alert if the vehicle drifts out of its lane. The system, available in commercial trucks since 2000, is now an option when purchasing the Infiniti M sedan and FX SUV.
The 2008 Lexus LS 600h L will be fitted with an Advanced Pre-Collision System comprised of two small cameras mounted on the front of the car, a millimeter-wave radar created to detect pedestrians in the car's path, and a third camera, placed on the steering column, to observe the driver. If the driver is not looking forward for a few seconds and there is an obstruction in front of the car, the system warns the driver with an alert chime and blinking light. As the car approaches the obstacle, the system makes the brakes ready to apply additional force if necessary, while adjusting the steering response and tightening passenger restraints to prepare for impact.
There is concern amongst some experts that these alerting devices will give drivers a false sense of security, persuading them to keep driving while they are impaired. So while the advances are encouraging, there's still no substitute for being well rested.
Most experts believe stricter enforcement is key to changing behavior, but it's not a cut-and-dried case. After an accident, the driver is most commonly found wide awake. No roadside test exists to determine a driver's level of fatigue.
But drivers who fell asleep at the wheel and admit they killed or maimed others aren't always charged or convicted. Victims and their families believe it's time Americans wake up to the risk sleep-deprived drivers create for everyone. Carole McDonnell's 20-year-old daughter, Maggie, perished after a driver who had been awake for more than 30 hours fell asleep, crossed three lanes and hit her head-on in 1997. McDonnell was aghast when the driver was ordered to pay a $200 fine for killing her daughter. "The defense hammered over and over to the jury that there was no law in the state of New Jersey stating you cannot sleep and drive," McDonnell says. Those words compelled her to take action.
New Jersey passed Maggie's Law in 2003, which makes it a criminal offense to be the driver in a fatal crash that results from the sleepiness and inattention of a driver who has been awake for more than 24 hours. In August 2005, McDonnell attended the sentencing of the first person convicted under Maggie's Law. "When I started this, I felt I was wronged by the courts, which I was," explained McDonnell. "I wanted whoever killed somebody like this to be punished. But it turned into something bigger and better."
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