California’s Graduated Driver Licensing Ten Years Later

Effects on Motor Vehicle Fatalities and Crashes through Age 25

Abstract

California’s 1998 Graduated Driver Licensing (GDL) law imposed complex restrictions, enhanced supervision, and delayed licensure on new drivers under age 18. While initial researchers credited GDL with reducing fatalities among 16-year-olds, later research found larger fatality increases among the 18- and 19 age group of GDL “graduates.” This study uses Center for Health Statistics and Fatality Analysis Reporting System traffic data from 1996-2008 to conduct time-series analyses of the longer-term effects of California’s GDL law on motor vehicle fatalities and fatal crashes among the 16-25 age group. The control series consisted of Californians in the 27-39 age group during the same time period who reached age 16 before GDL took effect. The analysis found that from 1996-2008, the 16-25 age group subjected to GDL suffered significant net increases of 5% in drivers’ fatal crash involvements and 7% in traffic fatalities compared to the control group not exposed to GDL. Declines in fatalities and fatal crashes among the 16-17 year old age group were more than offset by larger increases in fatalities and fatal crashes among ages 18-25. For the 16-25 age group as a whole, California’s GDL was associated with approximately 60 more fatal crashes and fatalities per year. These results replicate and extend the negative findings regarding GDL. They suggest that lawmakers now should consider repealing or substantially modifying California’s GDL in the direction of a more flexible, professional licensing system.