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Enforcement and Compliance with
GDL Provisions

The Teen Driver Safety Research team at The Children's Hospital of Philadelphia Research Institute is working to reduce the frequency and severity of crashes involving teens behind the wheel. Graduated Driver Licensing (GDL) programs are a cornerstone of public policy aimed at reducing the burden of crashes on adolescent health. Further reductions in teen crash rates will rely on strengthening specific provisions of, as well as greater enforcement of, GDL laws.

The following line of research is currently underway:

  • Graduated Driver Licensing Decal Law Effect on Young Probationary Drivers
    On May 1, 2010 New Jersey enacted the first-in-the-nation decal provision (Kyleigh’s Law, P.L. 2009, c. 037 - S2314) as part of its GDL program. It requires all youths 16 to 20 years of age holding a permit or intermediate license (i.e., probationary license) to display a reflective decal on the front and back license plates of vehicles they are operating. The provision was enacted with the goal of facilitating police enforcement of GDL restrictions, and ultimately, decreasing teen driver crash rates.

    The first CHOP study published in 2012 found that crash involvement of an estimated 1,624 intermediate drivers was prevented in the first year after the decal's implementation, as well as a 9 percent decrease in the rate of police-reported crashes among intermediate drivers and a 14 percent increase in GDL-related citations issued to intermediate drivers. Significant effects were also observed for specific types of intermediate driver crashes. For instance, multiple-vehicle crashes decreased 8 percent and crashes involving an intermediate driver with peer passengers decreased 9 percent.

    The second CHOP study published in 2014  provides valuable evidence that NJ’s Graduated GDL decal provision is associated with a sustained two-year decline in crash rates among intermediate teen drivers. After comparing monthly rates of police-reported crashes in the four years pre-decal and two years post-decal, the researchers reported a 9.5 percent decline in the crash rate after the decal was implemented. Crash rate declines during this period were even more dramatic for older novice drivers, decreasing 13 percent per year for 18-year-olds and nearly 17 percent for 19-year-olds.

    Research is currently being conducted to better understand the mechanisms by which decals work to prevent crashes.

For more information on this research, please contact Allison Curry, PhD, MPH at (215) 590-3118 or

This research was supported by The Robert Wood Johnson Foundation and State Farm Mutual Automobile Insurance Company (State Farm®).

This project was supported by State Farm Mutual Automobile Insurance Company (State Farm®) - See more at:
This project was supported by State Farm Mutual Automobile Insurance Company (State Farm®) - See more at:

NJ decals

Watch a video about CHOP's 2012 study evaluating NJ's decal year one implementation.

Access Dr. Curry's Teen Driving Learning Modules from the Association of Prevention Teaching and Research.


Download and print this fact sheet about the research to share with policymakers

Further reading:

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