CHAPEL HILL -- For 16- and 17-year-old drivers, the risk of fatal injuries during motor vehicle crashes grows as the number of passengers in the vehicle increases, according to a new study. Authors of the study and a North Carolina highway safety expert say the results show graduated licensing systems are a good idea for young drivers.
Dr. Li-Hui Chen of the Johns Hopkins University School of Hygiene and Public Health and colleagues found the risk of death increased 40 percent if one passenger was present, 86 percent if there were two and 182 percent with three or more passengers. For 17-year-old drivers, comparable percentage jumps in risk were 48, 158 and 207, respectively.
Chen, research associate at Hopkins' Center for Injury Research and Policy, is first author of a report appearing in the March 22 issue of the Journal of the American Medical Association. Dr. Robert D. Foss, a research scientist at the University of North Carolina Highway Safety Research Center, wrote the accompanying editorial.
Information analyzed in the study came from three federal sources; the Fatality Analysis Reporting System, the Nationwide Personal Transportation Survey and the General Estimates System. The first records U.S. highway traffic deaths, the second reflects driving patterns nationally and the third is a probability sample of U.S. police-reported crashes.
The risk of death increased for drivers transporting passengers regardless of the time of day or sex of the driver but males were at greater risk, the study showed. Young male drivers with three or more passengers driving late at night showed the most fatalities.
"In contrast, death rates per 10 million trips for drivers aged 30 to 59 years were lower for drivers with passengers than for those without passengers," Chen wrote. "Nighttime death rates greatly exceeded daytime death rates among 16- and 17-year-old drivers combined."
In his editorial, Foss offered his views on the findings.
The new study "provides sufficient evidence for policy-makers to improve the traffic safety of teen-age drivers, their passengers and other motorists," Foss wrote. "This can be achieved by prohibiting teen-agers in the second stage of (graduated driver licensing) systems from driving after 10 p.m. and from driving with teen-age passengers.
"The end result of prohibiting GDL second-stage teen-age drivers from transporting passengers would be to prevent some...deaths," he added. "In states without GDL systems or those with systems that do not prohibit driving with teen-age passengers, parents of 16- and 17-year-old drivers would be well advised to impose these restrictions themselves."
Motor vehicle death rates in the United States have declined dramatically during the past two decades because of technological improvements in vehicles and roadways, increased seat belt use and decreased alcohol-impaired driving, Foss wrote. However, death rates for 16-year-old drivers also have increased dramatically. Such inexperienced drivers not only unintentionally threaten their own and their passengers' lives, but also the lives of occupants of other vehicles.
Twenty-four states have enacted graduated driver licensing and despite their newness, studies already have shown declines of crashes among beginning drivers ranging from 7 percent to 32 percent, he said.
During 1998, only 5 percent of fatally injured 16-year-old drivers had been drinking alcohol, according to the National Highway Traffic Safety Administration. Although the proportion of fatally injured 17-year-old drivers who had been drinking climbed to 14 percent, that was only half the rate of fatally injured drinking drivers aged 21 to 29.
"Thus, although alcohol use by young drivers is clearly dangerous, it is apparent that the contribution of alcohol to crashes pales in comparison to inexperience, impulsiveness and poor judgment by drivers and distractions by passengers," Foss wrote.
Note: Chen can be reached at (410) 955-6878. Although out-of-town, Foss can be reached via e-mail at ROB_FOSS@unc.edu or by phone at (919) 962-8702. He will be back in his UNC-CH office March 23.
Contact: David Williamson, (919) 962-8596.
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