This article reviews the literature on the prevalence of sleep-related motor vehicle crashes and presents a detailed analysis of the driver and context variables associated with a sample of 1,269 sleepy-driver, fatal and injury-causing vehicle crashes that occurred over a 6-year period in Tennessee. The crash profiles and trends are discussed in terms of their implications for addressing this significant problem in highway safety. Findings suggest that younger drivers, ages 15-21, are more at-risk for sleep-related motor vehicle crashes. Also, there is some evidence for the effectiveness of rumble strips in reducing sleep-related, run-off-road, interstate crashes.