Journal of Safety Research

Journal of Safety Research

Volume 34, Issue 1, 30 January 2003, Pages 63-69
Journal of Safety Research

Graduated driver licensing in the United States: evaluation results from the early programs

https://doi.org/10.1016/S0022-4375(02)00080-4Get rights and content

Abstract

Background: Seventeen states enacted graduated driver licensing (GDL) programs that were implemented from 1996 through 1999 and for which evaluations are of interest. Methods: We received evaluation results reported for six states for which data were available. Summarizing results is difficult in other than the most global terms because of differences in pre-GDL programs, differences in GDL programs, and differences in evaluation methodology. Results: All states identified some crash reduction among teen drivers following GDL implementation. This positive effect was observed across different geographic regions, and with different GDL programs. Simple counts are down—fewer teens are experiencing crashes and becoming injured. After calculating crash rates to adjust for changes over time in populations or licensed drivers, reductions generally were still found. Population-adjusted risks of injury/fatal crash involvement of 16-year-old drivers in Florida and Michigan were reduced by 11% and 24%, respectively. Population-adjusted risks of any crash involvement of 16-year-old drivers in Michigan and North Carolina were reduced by 25% and 27%, respectively. Reductions in night (restricted hours) crash risk were impressive in Florida, Michigan, and North Carolina. A comparison state design was only possible in the Florida evaluation, and results showed greater crash reductions under GDL. Change-point analyses of Michigan's crash data trends over time provided additional support of GDL's effectiveness in reducing crashes. Discussion: Taken as a whole, and including the preliminary findings from California, Ohio, and Pennsylvania, these reports demonstrate the early effectiveness of GDL in reducing the crash risk of teen drivers. The impact of these studies and others to come will guide future research, practice, and policy.

Section snippets

Background

Unintentional injury from motor vehicle crashes is the number one cause of death among teenagers in the United States Centers for Disease Control and Prevention, 1997, National Highway Traffic Safety Administration (2002). Crash rates among young drivers age 16–19, per mile driven, are higher than those for all other age groups (Insurance Institute for Highway Safety [IIHS], 2000a) and the crash risk among 16- to 17-year-old drivers is almost three times as high as among 18- to 19-year-old

Methods

Typically, evaluations of GDL programs have used state crash data to determine the effect of the new GDL program on crashes, comparing crashes after the program to crashes before the program. Few evaluations have been able to include more than a year or two of data before and after program implementation, although a longer series would be desirable. Usually, a crash rate is determined based on the number of licensed drivers in the age group of interest, or based on the size of the state's

Results

Florida's GDL program was implemented July 1, 1996. The published evaluation of that program used pre- (1995) and post-program (1997) comparisons of 15- to 17-year-old driver fatal and non-fatal-injury crash rates (per capita), as well as a comparison with a border state, Alabama, which did not have GDL (Ulmer, Preusser, Williams, Ferguson, & Farmer, 2000). A reference group of older persons (25–54 years old) unaffected by the program was used in the analyses. Overall, there was a 9% reduction

Discussion

It is too soon to know if the observed crash reductions are due to young people driving more safely than previous to GDL. More likely, the reductions are due to reduced exposure. None of the studies above reported young drivers' exposure in terms of driving mileage or driving time so that it could be determined whether decreased driving exposure contributes to the decreased crash risk. However, there are indications that it is taking longer than previously for teens to become fully licensed to

Acknowledgements

This work was partially supported by the National Highway Traffic Safety Administration.

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