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Fall 2011 | Vol. 13 | No. 3
Controversial Study Suggests Mixed Results for GDL Laws
In its September 14, 2011 issue The Journal of the American Medical Association published an article examining the association of Graduated Driver Licensing (GDL) programs and teen driver-related traffic fatalities.
The study, Graduated Driver Licensing and Fatal Crashes Involving 16- to 19-Year-Old Drivers, concludes that while GDL programs are helpful in reducing fatalities related to 16-year-old drivers, the number of fatalities involving 18-year-olds has actually gone up.
Researchers looked at quarterly data from 1986-2007 showing the incidence of fatal crashes involving 16- to 19-year-old drivers for all 50 states and the District of Columbia. They found that the rate of fatal accidents involving 16-year-olds was 26 percent lower in states that prohibited teens from driving at night and carrying certain passengers, compared to states with neither restriction. However, these same states saw a 12 percent increase in the fatal crash rate involving 18-year-old drivers.
Lead author Scott V. Masten, a researcher at the California Department of Motor Vehicles, says “Right now, we’re not getting the net effect across all teens that we’re hoping for. We’re getting this washout where we do save some lives overall, but not nearly what we thought it [would be].”
The article does not purport to conclude what caused the uptick in fatalities associated with older teen drivers speculates, but authors speculate that some GDL programs may prevent younger teens of getting valuable driving experience and could lead some to wait to get a license after they turn 18, when the GDL restrictions would no longer be in effect in most states.
While Anne McCartt, Ph.D., Insurance Institute for Highway Safety senior vice president for research, acknowledges that the increase in fatalities associated with older teen drivers was not expected and should be further examined, she notes that “I don’t think there’s any study that hasn’t found a large benefit for 16-yearolds.” Barbara Harsha, Executive Director of GHSA said, “States should not get the message that GDL does not work. To the contrary, GDL has been one of the most effective highway safety countermeasures for young drivers.”
A possible limitation is that researchers reviewed only fatalities, which represent a small fraction of all teen-driver related crashes. Additionally, the nationwide results may not reflect the success of specific GDL programs, since the restrictions and requirements can vary so much from state to state.
Study authors suggest that future research should be done to determine the cause of the increased fatalities involving 18-year-old drivers and whether GDL program modifications can mitigate this effect.
For the article abstract, visit: http://jama.ama-assn.org/content/306/10/1098.abstract.