Objectives: Older drivers have become a larger part of the driving population and will continue to do so as the baby boomers reach retirement age. The purpose of this study was to identify the potential effects of this population increase on highway safety. Methods: Driver involvement rates for all police reported crashes were calculated per capita, per licensed driver, and per vehicle-mile of travel for 1990 and 1995. Also, driver involvement rates for fatal crashes were calculated for 1983, 1990, and 1995. Based on current crash rates per licensed driver and estimates of the future number of licensed drivers, projections of crashes involving drivers aged 65 and older were made for years 2010, 2020, and 2030. Results: Driver crash involvement rates per capita decreased with age, but fatal involvement rates per capita increased starting at age 70. The same pattern existed for involvement rates per licensed driver. For both all crashes and fatal crashes, involvement rates per mile driven increased appreciably at age 70. Using projections of population growth, it was estimated that for all ages there will be a 34% increase in the number of drivers involved in police reported crashes and a 39% increase in the number involved in fatal crashes between 1999 and 2030. In contrast, among older drivers, police reported crash involvements are expected to increase by 178% and fatal involvements may increase by 155% by 2030. Drivers aged 65 and older will account for more than half of the total increase in fatal crashes and about 40% of the expected increase in all crash involvements; they are expected to account for as much as 25% of total driver fatalities in 2030, compared with 14% presently. Conclusions: By most measures, older drivers are at less risk of being involved in police reported crashes but at higher risk of being in fatal crashes. Although any projections of future crash counts have inherent uncertainty, there is strong evidence that older drivers will make up a substantially larger proportion of drivers involved in fatal crashes by 2030 because of future increases in the proportion of the population aged 65 and older, and trends toward increased licensure rates and higher annual mileage among older persons. Countermeasures to reduce the anticipated death toll among older drivers should address the increased susceptibility to injury of older vehicle occupants in crashes.