The main aim of this research was to study the effects of a specific exercise program on the speed of behavior of older adults during on-the-road driving. Twenty-six drivers (55-78 yr old) were randomly assigned to either an exercise group or a control group. The exercise program (3 sessions of 60 min/wk for 8 wk) incorporated tasks that induced the participants to respond quickly to challenging situations. On-the-road driving tasks (under single- and dual-task conditions) included measures of simple and choice reaction time, movement time, and response time. Significant positive effects were found at follow-up resulting from participation in the exercise program: Improvements were found for several measures in all driving tasks, and a composite score reflected a better general drivers' speed of behavior. These results show that exercise can enhance speed of behavior in older drivers and should therefore be promoted.