Center for Injury Research and Prevention

New Jersey GDL Decals and Vehicle Identifiers Research

NJ GDL decal research

In 2010 New Jersey implemented a Graduated Driver Licensing (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.

Allison E. Curry, PhD, MPH is leading the NJ GDL decals and vehicle identifiers 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.

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 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.

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 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.

Read the study abstract. 

Read a blog post about the research.

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

Young Driver Compliance With Graduated Driver Licensing Restrictions Before and After Implementation of a Decal Provision

The third CHOP study, published in the Journal of Adolescent Health in 2018, evaluated whether the decal provision was associated with an increase in compliance with passenger and nighttime restrictions. Although findings do not suggest that the decline in crash rates following implementation was due to increased compliance with nighttime or passenger restrictions, additional research is needed to understand mechanisms by which decal provisions may reduce young driver crashes.

Read the study abstract

Read a blog post about the research.

Principal Investigator: Aimee J. Palumbo, PhD, MPH; Funding: Eunice Kennedy Shriver National Institute of Child Health and Human Development at NIH