This study used the CORSIM traffic simulation model to evaluate the effectiveness of a emergency vehicle signal preemption. The study consisted of three intersections on Leesburg Pike (Route 7) near the location of a hospital. Leesburg pike is a major commuter route for the Washington DC area. The approach was to use real world traffic data from the intersections for a base case scenario. This information would be coded into the CORSIM model to determine the possible effects on providing emergency vehicle preemption on the three intersections. Results showed that the impact on other traffic is statistically significant, however, it is minimal with a 2.4 percent increase in average travel time when priority is requested.