Emergency vehicles receive priority at traffic signals via emergency-vehicle preemption mechanisms. To guarantee emergency vehicles can pass through in a timely manner and without delay, the preemption mechanism must interrupt normal operation of traffic signals, one at a time, along the vehicle’s path, causing each intersection to fall out of coordination. 

This procedure can cause major increases in overall traffic delay. New GPS-based priority mechanisms are undergoing pilot studies at several U.S. locations. Such systems have advantages and disadvantages and need to be evaluated to determine the conditions under which a system should be used and the optimal configuration of the selected system. 

This project will investigate each system and provide tools and guidelines to provide right-of-way priority to emergency vehicles through signalized intersections while optimizing the overall system performance.