The relative impact of a self-management for safety (SMS) process was evaluated at two short-haul trucking terminals. Participants in the Pre-Behavior group (n = 21) recorded their intentions to engage in specific safe versus at-risk driving behaviors before leaving the terminal (i.e., before making any of their deliveries for the day), whereas participants in the Post-Behavior group (n = 12) recorded their actual safe versus at-risk driving behaviors after returning to the terminal (i.e., after making all their deliveries for the day). Each participant drove a truck equipped with an on-board computer-monitoring device that recorded two driving behaviors, traveling at speeds greater than 63 mph (overspeed) and stopping or braking at speeds greater than or equal to 7 mph/sec (extreme braking). During the SMS intervention, participants in the Pre-Behavior group reduced their mean percentage of time overspeeding by 30.4%;, and their mean frequency of extreme braking incidents by 63.9%;. Similarly, during the SMS intervention, the Post-Behavior group reduced their mean percentage of overspeeding and their mean frequency of extreme braking incidents by 19.3% and 49.4%, respectively.