CEVPDS: A Cooperative Emergency Vehicle Priority Driving Scheme for Improving Travel Efficiency Through V2X Communications

Emergency vehicles (EmVs) play a crucial role in providing prompt services to public rescue activities. However, due to the impacts of ordinary vehicles (OVs), EmVs are often blocked and cannot reach the rescue site in time. Therefore, a cooperative emergency vehicle priority driving scheme (CEVPDS) is proposed to ensure the EmVs’ travel efficiency. The proposed scheme is used for urban express roads under a vehicle-to-everything communications (V2X) environment and consists of two steps to ensure high-priority passage for the EmVs to reach the rescue accident site. The first step involves designing the EmV trajectory in advance. The second step requires the OVs to dynamically give way to the EmV by lane changing according to the EmV’s pre-planned trajectory established in the first step. Once the EmV trajectory is predefined, the relevant trajectory information is transmitted to surrounding OVs via V2X communication. OVs ahead of the EmV are then scheduled to provide adequate road space by lane changing, while the OVs behind it are prohibited from overtaking it. We conducted simulations using the SUMO platform. Compared with the Fixed-Lane Strategy (FLS), the proposed scheme achieves multiple improvements in multiple aspects: it drastically shortens the EmVs response time, significantly mitigates the impacts on OVs, and fewer lane changes for both EmVs and OVs. As a result, the scheme not only enhances the travel efficiency of EmVs but also guarantees the safety, symmetry, and efficiency of the overall urban traffic system.