Car crashes involving teen drivers, in which they are overwhelmingly at fault, kill far more teens each year than any other cause, arguably making driving the greatest public health threat facing U.S. teens. Teens crash at rates far higher than those of older drivers, and the younger the teen driver, the higher the risk—16-year-old drivers have crash rates 250% higher than those of 18-year-olds. Research has established that the differences in crash risk among teens at younger ages results only partly from inexperience; instead, their increased crash risk primarily results from immature regulatory competence that develops only with time, and age. The United States is the earliest-licensing nation in the developed world, moreover, with U.S. teens having a greater risk of being killed or injured in a car crash than their counterparts in other developed nations. Despite the tremendous costs to public health imposed by adolescent licensure and driving, and their implications for a range of legal and policy issues, neither legal academics working in public health law nor those working in adolescent rights have focused attention on adolescent licensure. This article is thus the first to interrelate research from the social and developmental sciences, and, cognizant of political challenges and constitutional boundaries, make a sustained argument for the most effectual legal reforms to which it inexorably points.