268752 Graduated Driver Licensing and Motor Vehicle Crashes involving Teenage Drivers: An Age-Stratified Meta Analysis

Sunday, October 28, 2012

Motao Zhu, MD, MS, PhD , Dept. of Community Medicine and Injury Control Research Center, West Virginia University, Morgantown, WV
Peter Cummings, MD, MPH , School of Public Health and Harborview Injury Prevention & Research Center, University of Washington, Seattle, Bishop, CA
Haitao Chu, MD, PhD , Division of Biostatistics, University of Minnesota, Minneapolis, MN
Jeffrey H. Coben, MD , Injury Control Research Center, West Virginia University, Morgantown, WV
Guohua Li, MD, DrPH , Departments of Anesthesiology and Epidemiology, Columbia University, New York, NY

As a policy intervention to reduce traffic injuries involving adolescent drivers, Graduated Driver Licensing (GDL) has been implemented in Australia, Canada, New Zealand, and the United States. Our goal was to summarize available data to estimate whether any GDL effects varied with age.


We searched MEDLINE, Transportation Research Information Service, and other sources for studies from 1991-2011. Out of 1,397 papers identified, 144 were screened by abstract and 43 were reviewed. Adjusted rate ratios (aRR) for crash outcomes were pooled using a random effects method. Rate denominators were estimates of person-time.


Fourteen studies from 13 US states and one Canadian province were included. The pooled aRR for the association of GDL law presence with crash rates was 0.79 (95% confidence interval [CI]: 0.74 to 0.85) for drivers age 16 years, 0.96 (95% CI 0.93 to 0.99) for age 17, and 1.02 (95% CI: 0.97 to 1.08) for age 18. The difference among these three rate ratios was statistically significant: p = <0.001. The aRR was 0.95 (95% CI 0.93 to 0.97) for drivers age 17 years where they could not drive after 11 pm or midnight, and 1.05 (95% CI 0.98 to 1.12) where there was no nighttime driving restriction or no change in nighttime driving restriction.


GDL policies reduced motor vehicle crashes among 16-year-old drivers by about 21%, but had less influence on rates for 17-year-old drivers. These estimates do not support the theory that GDL laws increase crash rates for drivers age 18 years.

Learning Areas:
Public health or related laws, regulations, standards, or guidelines
Public health or related research

Learning Objectives:
1) Differentiate the effects of graduated driver licensing on traffic crashes according to adolescent age. 2) Explain the systematic review and meta-analysis method in epidemiological studies of injury.

Keywords: Adolescent Health, Injury

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: Because I designed and conducted the study
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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