ROUTE-BASED DYNAMIC PREEMPTION OF TRAFFIC SIGNALS FOR EMERGENCY VEHICLE OPERATIONS

A route-based dynamic strategy is developed for efficient preemption of traffic signals for emergency vehicles in real time. The proposed method combines an on-line route selection module and a sequential dynamic preemption strategy, so that traffic queues at the intersections on a given emergency route can be cleared in advance for an emergency vehicle, while minimizing delay because of unnecessary preemption. The proposed strategy was simulated in a real traffic network using a microscopic simulation model, which was calibrated with the emergency vehicle travel time data collected from the sample network. The performance of the proposed dynamic preemption was compared with that of the existing intersection-by-intersection preemption strategy which was also modeled and simulated in this study. The simulation results clearly indicate substantial benefit of the proposed strategy over the existing method for the long and complicated routes in reducing the travel time of an emergency vehicle, while maintaining compatible network-wide traffic performance