Long Hours, Little Sleep Contribute to Drowsy Driving Crashes, Study Shows
21 December 1999
Long Hours, Little Sleep Contribute to Drowsy Driving Crashes, Study ShowsWASHINGTON, Dec. 21 -- In the first-ever study of its kind, the AAA Foundation for Traffic Safety and the University of North Carolina Highway Safety Research Center (HSRC) studied hundreds of sleep and fatigue- related car crashes to identify the driver behavior that caused them. Factors strongly associated with having a drowsy driving crash included sleeping less than six hours per night, being awake for 20 hours or longer, working more than one job and/or working night shifts, and frequent driving between midnight and 6 a.m. With 35 million drivers about to travel for the holidays, this issue is particularly timely. "Previous studies about drowsiness and driving were done in a laboratory," says David K. Willis, President of the AAA Foundation for Traffic Safety. "This is the first time anyone has looked at real-world crashes to see what happens. And what happens is that drivers who have had six or less hours of sleep or who often drive between midnight and 6 a.m. put themselves at very high risk." The study was performed by Dr. Jane Stutts of the HSRC with Drs. Bradley Vaughn and Jean Wilkins of the UNC School of Medicine. Researchers who used police crash reports and driver records to identify and interview 1,400 drivers. The sample included four groups: drivers who fell asleep, drivers who were fatigued, drivers who crashed for non-sleep reasons, and a control group of drivers who had not had a crash in three years. The researchers administered a detailed questionnaire about the drivers' work schedules, sleep habits, quality of sleep, amount of driving, and the circumstances surrounding their crash. Drivers were also asked questions to assess their present levels of sleepiness. Large differences were found among the groups. Sleep and fatigue crash drivers had been awake longer and had slept less -- just a fifth of them reported getting 8 or more hours of sleep before the crash, compared with nearly half of the control group. Drivers in sleep and fatigue crashes were also more likely to deal with their drowsiness once they were on the road rather than by planning ahead and taking precautions such as getting enough sleep or using caffeine. The study indicated that many drivers do not know how sleepy they are. Around half the drivers in sleep-related crashes said they did not feel even moderately drowsy before they crashed. "People need to think about sleep even when they don't feel tired," Willis says. "Driving with your eyes closed can kill you." The AAA Foundation for Traffic Safety is a not-for-profit charitable organization funded by donations from AAA and CAA clubs and members. It is devoted to preventing crashes and saving lives through research and education in the field of traffic safety. The full study may be found on the AAA Foundation's web site, http://www.aaafoundation.org.