This paper summarizes the first comprehensive evaluation of vehicle assist and automation (VAA) technology in bus revenue service by a U.S. transit agency. The technology in question is a GPS-based technology suite used by the Minnesota Valley Transit Authority for vehicle guidance in the shoulder. Called the Driver Assist System, or DAS, it provides accurate lane position feedback to the driver via a headup display, virtual mirror, vibrating seat, and actuated steering. The evaluationconfirmed that the DAS improved bus operations and reduced driver stress. Drivers stayed in the shoulders 4.3 percent longer, drove 3.5 miles per hour faster, and reduced their side-to-side movement by 4.7 inches when the DAS was activated. The changes in speed and side-to-side movement were statistically significant at the 95% confidence level. In surveys, a majority of the drivers believed the DAS made driving in the shoulder safer and less stressful.