MAG conducted a study about current Emergency Vehicle Preemption (EVP) practices in the MAG region. The findings of the study are organized into four sections:
EVP is done by adjusting traffic signals. This starts with communications between a receiving device on a traffic signal and an emitter on an approaching emergency vehicle. The goal is to ensure the emergency vehicle’s safe passage through the intersection. Emergency vehicles with an emitter can request traffic signal preemption as they near an intersection. Several areas in the MAG region installed EVP systems after the technology was introduced in the early 1980s. With a goal of reducing response times, EVP capability is considered by first responders and transportation agencies an essential function of traffic signal operations.
While the Manual on Uniform Traffic Control Devices (MUTCD) specifies the standards for going into and out of preemption, there is a lack of guidance in the vital aspects of EVP operations. This includes preemption signal phase, confirmation light, data encryption, and needed inter-agency coordination to support emergency response automatic or mutual aid agreements. The distinction of inter-agency support is important. The Valley Wide Automatic Aid system involves a centralized dispatch by Phoenix Alarm. This results in the nearest emergency resource, regardless of agency and geographical boundaries, responding to the event. Mutual aid agreements are in place so agencies will support each other. This MAG EVP State of the Practice Study intends to address these knowledge gaps by identifying priority issues and recommending feasible approaches toward improved regional coordination.