The "actor/driver" in the VRSIM was a virtual model of a person sitting in a standard commercially available EPW power wheelchair (width 0.671 m, length 0.701 m). A horizontal slider bar that indicated the real time location of the virtual wheelchair with respect to virtual obstacles was added to this version (Fig.1, 2). This helped display warnings when the chair was too close to obstacles, especially when the obstacles were behind the driver. Participants were expected to drive along the course indicated by arrows touching or passing through preset milestone markers signified by semi-transparent balloons. These sequentially displayed milestones defined the tasks of the virtual PMRT. Participants were instructed to complete every task as quickly and accurately as possible. An equivalent PMRT driving course was charted out in an office space for the real world driving evaluation.