WSN-EVP: A Novel Special Purpose Protocol for Emergency Vehicle Preemption Systems

Emergency Vehicle Preemption (EVP) systems play a key role in reprioritizing signalized traffic intersections. This role is important for safe and minimum travel delay of emergency vehicles (EV) passing through road intersections. Unfortunately, conventional systems that are currently in use on the roads have deficiencies in terms of cost, reliability, maintainability, and scalability. In this paper, a novel approach is proposed utilizing batteryless wireless sensor networks (WSNs) to overcome the above difficulties and improve the safety and mobility of emergency vehicles. A special purpose preemption protocol is designed based on the collection tree protocol (CTP) as a data collection service. The protocol is called WSN-EVP and is used to handle the EV preemption request in a multi-hop tree-based topology spread across the traffic intersection. The model functions according to predefined rules and optimized parameters to cope with the high topology changes and the fast response time requirement. A prototype implementation using TelosB motes programmed in nesC shows a performance of high preemption accuracy under high level of interference.