A traffic signal control algorithm for emergency vehicles

Signal preemption disrupts normal traffic signal to allow emergency vehicles to pass \nthrough the intersection more safely and quickly. In medical emergency situations, \nEVP (Emergency Vehicle Preemption) offers a faster response to the sufferer which \nimproves the chance of survival. Despite this lifesaving advantage, conventional preemption \nhas some problems which need more attention. Two important issues are \nincreased delay of overall traffic due to preemption and absence of prioritization of \nconflicting preemption requests. \nThis thesis presents a traffic signal control algorithm that addresses the above. \nWe have used TSP (Transit Signal Priority) techniques to improve the EVP system. \nTSP is a proven strategy to provide a better quality public transit operation in urban \nareas. Our proposed algorithm adjusts signal phases using TSP techniques to serve \nan emergency vehicle. We consider both single and multiple simultaneous emergency \nvehicle requests. TSP techniques help us to alleviate the impact on general traffic. For \nmultiple emergency vehicle requests, a branch and bound algorithm is developed that \nprioritizes among conflicting requests. Experiments have been conducted using the \nVISSIM microscopic traffic simulator. Results show that the proposed traffic control \nalgorithm reduces overall traffic delay by up to 8% compared to conventional EVP \nsystem.