A Priority Algorithm to Control the Traffic Signal for Emergency Vehicles

Signal preemption disrupts normal traffic signal to allow emergency vehicles to pass through the intersection more safely and quickly. In emergency situations, EVP (Emergency Vehicle Preemption) offers a faster response to the sufferer. Despite this lifesaving advantage, conventional preemption has some problems which need more attention. Increasing delay on overall traffic and failure to prioritize among conflicting preemption requests are two important issues to address. This paper presents a priority signal control algorithm to deal with these issues. We have used TSP (Transit Signal Priority) techniques to improve the EVP system. TSP is a proven strategy to provide a better quality public transit operation in urban areas. Our proposed algorithm adjusts signal phases using TSP techniques to serve an emergency vehicle. These techniques help us to alleviate the impact of EVP on general traffic. Experiments have been conducted using the VISSIM microscopic traffic simulator. Results show that the proposed traffic control algorithm reduces overall traffic delay by up to 8% compared to conventional EVP system.