Previous studies have demonstrated that both inexperience and developmental factors (often operationalized as age) are important predictors of young driver crash risk. However, few previous studies have concurrently assessed the influence of both age and experience on young driver crashes, and no US study has done so in the post-Graduated Drivers Licensing (GDL) era. Further, while the sharp increase in crash risk that occurs at the point of transition between a learner’s permit and intermediate license has been well described, little attention has been given to the transition from intermediate to full licensure. Thus, the objective of this study was to use a linked licensing-crash database from New Jersey to examine the independent and joint contributions of age at licensure, driving experience, and GDL license phase on 24-month crash rates among the population of New Jersey (NJ) drivers who were first licensed from 17 through 20 years old. A recently constructed unique database was used linking data from two administrative sources–the NJ Motor Vehicle Commission’s Licensing and Registration Database and the NJ Department of Transportation’s Crash Record Database. For this study, all drivers were selected who obtained their NJ intermediate license at 17-20 years old and from 2006 through 2009 (n=410,230). The exact age was determined at which each driver obtained an intermediate and full license and created distinct, fixed cohorts of drivers based on their age at intermediate licensure. For each cohort, observed monthly crash rates calculated and graphed over the first 24 months of licensure. Further, crash rates were examined by age at licensure, driving experience (as measured by time since licensure), and GDL licensing phase. (Author/publisher)
Abstract