The objectives of this research were to provide answers to the following questions: What was the overall reduction in involvement of 16-year-old drivers in fatal crashes and injury crashes? Did crash involvement rates decline as the number of restrictive components in GDL programs increased? How much could crashes of 16-year-old drivers be reduced if all states had GDL programs as effective as the programs associated with the largest reductions? If an association is found between GDL and lower crash rates, does it appear to be a causal relationship? This study is based upon analysis of data on fatal crashes, compiled and made available to the public by the National Highway Traffic Safety Administration; midyear population estimates, compiled and made available to the public by the U.S. Census Bureau; data on injury crashes, compiled by individual states and obtained specifically for this study with the permission of each respective state; and information on state GDL legislation, provided by AAA Government Relations & Traffic Safety Advocacy, the Insurance Institute for Highway Safety, and representatives of individual states.