Duke 2008 | ASHE | Equity and Efficiency in Health and Healthcare

The literature on teenage driving indicates that teenagers are at elevated risk for motor vehicle crashes. In 2003, teenagers (ages 13-19) accounted for 10% of the U.S. population, and 13% of motor vehicle crash deaths. In 2001, motor vehicle crashes were the top reason for death among the teenagers. 41% of the female teenage fatalities and 34% of the male teenage fatalities resulted from a motor vehicle crash. Various studies have attributed this increased risk level to factors such as the fact that teenagers have low level of driving experience, tend to drive at riskier times (night-time), and usually carry other teenage passengers in their car, leading to a distracting environment for the driver. Starting in 1996, states have responded to these concerns by adopting graduated driver licensing (GDL) policies to reduce traffic hazards for teenagers. Previous literature evaluating the impact of graduated driver licensing (GDL) policies of the 1990s has demonstrated the policies' effectiveness on reducing teenage involved fatal crashes. However, much remains unanswered: Why do they work? How do they work? Will the initial effects erode? How might they be improved? The difficulty in answering questions above have been due to the unavailability of good estimates of how many teenage drivers are on the roads at any given time, and how that varies with the GDL policies. To fill this gap, our primary aim is to assess whether these policies achieve favorable results by improving teenage driving behavior, or by simply limiting the amount of teenage driving temporarily. We first build a structural model that separately identifies the amount of teenage driving and the riskiness of teenage driving relying on data from two-car crashes and the information contained in the relative numbers of crashes between two teenagers, two adults versus a teenager and an adult. Next the relative amount of teenage driving and teenage driving risk are related to the GDL policies as well as other state-year level driving related laws and demographic information. The model is estimated jointly in a two-level hierarchical modeling framework. The primary data sources are the Fatal Accident Reporting System, a universe of all fatal crashes in the U.S., and the State Data System, a universe of all police reported accidents (fatal and non-fatal) for a select number of states that provide the data. The study period is 1990 to 2005. We find that the GDL policies have mainly reduced the number of teenage fatal accidents by improving teenage driving behavior rather than by limiting the amount of teenage driving. Stricter GDL policies have been significantly more effective.