Research Papers

This study summarizes methodological issues surrounding studies of  compliance with Graduated Driver Licensing (GDL) restrictions among young drivers with intermediate driver's licenses. The study uses a novel application of the quasi-induced exposure (QIE) technique to the measurement of GDL compliance among young drivers in New Jersey. Using the QIE method, the study estimated that 8% of drivers' trips were not in compliance with the GDL passenger restriction. 

After linking NJ’s statewide driver licensing and crash databases, this study found that 92% of intermediate drivers’ trips followed the passenger restriction of GDL and 97% followed the nighttime restriction of GDL. Compliance, however, was significantly lower among those living in low-income and urban areas, among male drivers, on weekends, and in summer.

This study is the first to estimate sensitivity and specificity of EHR-based ADHD diagnosis codes in classifying ADHD status. Findings show that the EHR-based algorithm was able to identify ADHD cases accurately and efficiently, proving that EHR-based diagnostic codes can be used by large-scale epidemiological and clinical studies with high sensitivity and specificity.

This study validated the quasi-induced exposure (QIE) methods used to assess young driver trends. These methods can be used to address broader foundational and applied questions in young driver safety.

The New Jersey GDL decal provision was implemented in May 2010, and this study found that it was not associated with a change in citation or crash rates among NJ drivers under 21 years of age with learner’s permits between January 2006 and January 2012. The findings contrast with previous research that found a significant decrease in the crash rates of drivers with intermediate licenses after the decal provision.

This study looked at licensing age, driving experience, and GDL license phase in relation to crash rates among young NJ drivers. Findings show that teen drivers have a steep increase in crash risk at the point of transition from intermediate to full licensure. These findings support the recommendation to extend the age requirement for the intermediate license phase to age 21.

This study found that 65% of 17-year-olds living in the highest-income zip codes were licensed in the first month of eligibility compared with 13% of those living in the lowest-income zip codes. Moreover, the younger one obtains an intermediate license, the earlier the graduation to a full license.

NJ’s 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 crash rate declined 9.5%. More research is needed to understand how these decals may work to reduce teen driver crashes.

Findings show that the Federal Highway Administration (FHWA) licensing data is not accurate when compared to NJ administrative licensing data. Future researchers should avoid using FHWA licensing data and instead encourage FHWA to work with state licensing agencies to improve the accuracy of its data.

Traditional methods for determining crash responsibility may not be accurate since issuance may vary by factors that are independent of fault, such as age and gender. These methods also do not capture driver behaviors that, while not unlawful, are still indicative of fault. An alternative method based on identifying crash-contributing driver actions should be used instead.