New Jersey has a licensing system that is unique in the United States. The licensing age is 17, compared with 16 in most states. New Jersey’s graduated driver licensing (GDL) system, introduced in 2001, includes provisions for novices of all ages. Maryland is the only other state where GDL features apply to drivers older than 18. Moreover, New Jersey’s system is one of the most comprehensive in the nation. Before 2001, a learner permit was available at age 16 and an unrestricted license at age 17. Beginning in 2001, the learner permit had to be held for at least six months, and the initial license included night and passenger restrictions for at least one year. Prior studies have shown that postponing licensure until age 17 provides a safety benefit. However, there has never been a comprehensive study of the combined effects of New Jersey’s higher licensing age and strong GDL. Driver crash rates per population for ages potentially affected by GDL were compared, pre- and post-GDL implementation, with those of an older age group (ages 25—59) that would not have been affected by GDL, using data on police-reported crashes of all severities from the New Jersey Department of Transportation and data on fatal crashes from the National Highway Traffic Safety Administration. After GDL implementation, there were statistically significant reductions in the crash rates of 17-year-olds, based on all crashes (16%), injury-only crashes (14%), and fatal crashes (25%), relative to those of drivers ages 25—59. The crash rates of 18-yearolds decreased significantly on the basis of all crashes (10%) and injury-only crashes (10%), relative to those of drivers ages 25—59. The fatal crash rate of 18-year-olds dropped by 4 percent. There was a statistically significant reduction in fatal crashes of 16-year-old drivers; however, this is unlikely to have been attributable to GDL. Under GDL, all 17-year-old drivers and many 18-year-old drivers in New Jersey are subject to restrictions on driving at night and driving with more than one passenger. Significant reductions in nighttime crashes (of all severity levels) of drivers ages 17 and 18 were observed, as were significant yet smaller reductions in their daytime crash rates. Due to data limitations, crashes involving young drivers with passengers could only be analyzed using data on fatal crashes; reductions in fatal crashes of 17- and 18- year-olds carrying more than one passenger were sizable (23% and 24%, respectively) but were not statistically significant. New Jersey’s combination of licensing policies for young drivers is a model for the nation. The licensing age of 17 eliminates most crashes at age 16. With respect to population-based fatal crash involvement rates of 17-year-olds (relative to ages 25— 59), New Jersey’s national ranking dropped from 45th prior to having implemented GDL to 21st currently; for 16- and 17-year-olds combined, New Jersey ranks second behind the District of Columbia. To the extent that the relative inexperience of 17-year-old New Jersey drivers negatively impacts their crash rate compared with 17-year-olds licensed at 16, this effect appears to be largely blunted by the strong GDL system. New Jersey’s GDL system also reduces crashes at age 18, an age group untouched by other states’ GDL systems. Provisions introduced to strengthen the night and passenger restrictions, effective in 2010, will likely extend the substantial safety gains that have been achieved thus far. (Author/publisher)
Abstract