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The U.S. Department of Transportation reports that up to 200,000 traffic accidents each year may be sleep related and that 20% of all drivers have dozed off at least once while behind the wheel. Truckers are particularly vulnerable. A long-haul driver covering up to 4,000 miles in seven to 10 days often averages only two to four hours of sleep a night. "I've followed trucks that were weaving all over the road," says Corky Woodward, a driver out of Wausau, Wis. "You yell, blow your air horn and try to raise them on the CB radio. But sometimes they go in the ditch. You ask what happened, and they can't remember because they're so tired."
No one knows how large a role fatigue has played in train and air disasters over the years, but the danger is undisputed. A drowsy engineer and crew were deemed the probable cause of the 1988 head-on collision of two Conrail freight trains near Thompsontown, Pa., a crash that cost four lives and $6 million. Long plane flights that cross through many time zones are more common than ever, and they often leave pilots suffering from jet lag. Yet today's highly automated cockpits require pilots to be especially vigilant in monitoring dials and digital displays. Says one pilot for an international air courier: "There have been times I've been so sleepy I was nodding off as we were taxiing to get into takeoff position." As the workplace becomes ever more technologically sophisticated, the price of disaster is higher. "So many more people can be hurt when a train engineer or a nuclear technician falls asleep in 1990 than when a stagecoach driver fell asleep in 1890," notes psychologist Merrill Mitler, director of sleep research at the Scripps Clinic in La Jolla, Calif.
Sleep-deprived workers may resort to alcohol and drugs as a way to compensate for fatigue. But the solution only compounds the distress. Many people wind up on a hurtling roller coaster, popping stimulants to keep awake, tossing down alcohol or sleeping pills to put themselves out, then swallowing more pills to get up again.
Putting in long hours and getting little rest are bad enough. But people who work unusual shifts face a double whammy. About 20% of U.S. employees toil during the evening or night hours, or rotate through day, evening and night duty. Such workers are both sleep starved and out of synch with their natural sleep-wake cycle. For most people, biological alertness peaks in the morning and early evening. It dips mildly in the afternoon (hence the tendency toward midday naps) and plummets between midnight and dawn. Night workers are butting against those rhythms, forcing themselves to stay awake just when their bodies are nudging them to tap out.
Researchers have documented an alarming increase in the frequency of mishaps during the graveyard shift of 11 p.m. to 7 a.m. For instance, between 4 a.m. and 6 a.m., the rate of fatigue-related accidents for single trucks is 10 times as high as the rate during the day. Experts say it is no surprise that the Exxon Valdez oil spill as well as the disasters at the Union Carbide plant in Bhopal, India, and the nuclear reactor at Three Mile Island occurred after midnight, when distractions are few and operators are liable to be at their drowsiest.