The effects of graduated driver licensing on teenage body weight.

The graduated driver licensing (GDL) program requires teenage drivers to pass through an intermediate stage, which contains specific driving restrictions such as a night curfew or a limit on the number of teen passengers to be carried, before earning full driving privileges. Using individual data from the 1999 to 2017 biennial Youth Risk Behavior Surveillance System (YRBS) combined with state-level GDL policy variations, we estimate the effects of GDL on teenage body weight in the United States. We find that the presence of GDL raises adolescents' body mass index Z-score and their likelihood of being overweight or obese. Among the restrictions imposed, a night curfew implemented together with a passenger restriction makes the most significant impact. These estimated effects are concentrated among states with more restrictive GDL policies. We also find that the presence of GDL reduces adolescent physical activity and heavy smoking, while increasing their time spent watching TV and milk intake, perhaps contributing to youth weight gain. An event study analysis reveals that the effects of GDL on adolescent weight increase may be transitory.