1. South Carolina Department of Health and Environmental Control, Columbia, South Carolina
2. Young Driver Behavior and Injury Prevention Group, University of Michigan Transportation Research Institute, Ann Arbor, Michigan
3. Department of Health Behavior and Health Education, University of Michigan School of Public Health, Ann Arbor, Michigan
4. Center for Law, Ethics, and Health, University of Michigan School of Public Health, Ann Arbor, Michigan
5. Department of Emergency Medicine and the Child Health Evaluation and Research (CHEAR) Unit, Division of General Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan