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GDL Decal Research

The Teen Driver Safety Research team at The Children's Hospital of Philadelphia Research Institute is conducting Graduated Driver Licensing (GDL) decal research to examine the effect of New Jersey's decal provision on enforcement and crashes among intermediate drivers. They are also conducting research to better understand the mechanisms by which decals work to prevent crashes.

The following line of GDL Decal Research is currently underway:

  • Effect of New Jersey's Graduated Driver Licensing Decal Provision Effect on Young Intermediate 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. Dr. Allison Curry and her team analyzed data from the New Jersey Traffic Safety Outcomes Program database to examine the effect of NJ's decal provision on enforcement and crashes among intermediate drivers.

    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 2015 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. Researchers compared monthly rates of police-reported crashes in the four years pre-decal and two years post-decal, reporting a 9.5 percent decline in the crash rate after the decal was implemented.  Intermediate driver crash rates decreased 1.8 percent per year before the provision and 7.9 percent per year in the post-decal period.

    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, State Farm Mutual Automobile Insurance Company (State Farm®) , and The National Institute for Child Health and Human Development.  

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:

GDL decal research

Watch a webinar on advocating for a decal provision in your state.

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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