Objective:​ This article presents a time-series analysis of changes in road safety in the United States from a public-health point of view.

Method:​ A 50-year period was examined, from 1958 to 2008. The emphasis was on the changes by decades in fatalities per population across different age groups.

Results:​ First, from 1958 to 2008, the overall fatality rate per population decreased by 40 percent. Second, the decrease in the rate was age dependent (with the largest decreases for the youngest and the oldest, and the smallest decreases for the middle-aged). Third, the overall fatality rate increased from 1958 to 1968, but it decreased for each of the 4 following decades. Fourth, the changes in the rate for each decade were age dependent. Fifth, the patterns of these age-dependent changes varied across the decades.

Conclusions:​ Examples of interventions that are likely to have age-dependent effects consistent with the obtained differential age changes in the fatality rate are discussed. However, other interventions are also likely to have relevant age-dependent effects on the fatality rate.