Recent changes in the age composition of U.S. drivers: implications for the extent, safety, and environmental consequences of personal transportation.

OBJECTIVE: This study examined the changes in the United States from 1983 to 2008 in the percentage of persons with driver's licenses as a function of age.
METHOD: The analysis used data from the Federal Highway Administration on driver's licenses by age.
RESULTS: (1) Over the past 25 years, there was a substantial decrease in the percentage of young people with a driver's license and a substantial increase in the percentage of older people with a driver's license. (2) For cohorts who were between age 20 and 44 in 1983 (and thus between age 45 and 69 in 2008), the percentage of licensed drivers has not changed appreciably between 1983 and 2008. This finding suggests that, for all practical purposes, all those who wanted to obtain a driver's license did so by age 20. (3) For cohorts who were between age 45 and 59 in 1983 (and thus between age 70 and 84 in 2008), this percentage dropped substantially. This finding reflects the surrendering of driver's licenses with advanced age.
CONCLUSION: The age composition of US drivers has changed substantially between 1983 and 2008. In 1983, the largest group of drivers included those between 25 and 29 years of age. In contrast, in 2008, the largest group included those 70 years and older.