New Jersey GDL Decals and Vehicle Identifiers Research

Many countries, including Great Britain, New Zealand, Australia, Canada, and France, have required GDL holders to identify their licensing status through the use of placards or decals (also known as L-plates and P-plates). These GDL identifiers and decals are required to be highly visible on any vehicle novice teen drivers operate. While some of these provisions have been in place for decades, they are a relatively new concept for GDL in the United States.
In 2010 New Jersey implemented a GDL provision requiring young novice drivers to display a decal on their vehicle indicating their license status (Kyleigh’s Law, P.L. 2009, c. 037 - S2314). The provision was enacted with the goal of facilitating police enforcement of GDL restrictions, and ultimately, decreasing teen driver crash rates. To date, only NJ requires the use of GDL decals by its learner and intermediate drivers.



Allison E. Curry, PhD, MPH is leading the NJ GDL decal and vehicle identifier research effort at CIRP, focusing on examining the effect of the provision on enforcement and crashes among young intermediate drivers. She and her team are also conducting research to better understand the mechanisms by which decals work to prevent crashes.

Although NJ has one of the most progressive GDL systems in the country, without this decal research the state would not have known empirically that its robust program reduces young driver crashes.

Research Projects

Graduated Driver Licensing Decal Law: Effect on Young Probationary Drivers

The first CHOP study published in the American Journal of Preventive Medicine 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% decrease in the rate of police-reported crashes among intermediate drivers and a 14% 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%, and crashes involving an intermediate driver with peer passengers decreased 9%.

Read the study abstract. 

Principal Investigator: Allison E. Curry, PhD, MPH 

Funding: The Robert Wood Johnson Foundation

Long-Term Changes in Crash Rates After Introduction of a GDL Decal Provision

The second CHOP study, published in the American Journal of Preventive Medicine in 2015, provides valuable evidence that NJ’s 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% decline in the crash rate after the decal was implemented. Intermediate driver crash rates decreased 1.8%  per year before the provision and 7.9%  per year in the post-decal period.

Read the study abstract.

Principal Investigator: Allison E. Curry, PhD, MPH

Funding: The Robert Wood Johnson Foundation; State Farm Mutual Automobile Insurance Company; Eunice Kennedy Shriver National Institute of Child Health and Human Development at NIH

Watch a webinar about CIRP's decal research and how to advocate for stronger GDL programs in  your state: