Intelligent Traffic Control Method for Emergency Vehicles Prioritization Based on DSRC Transportation System

Emergency Vehicles (EmVs) prioritization is critical to be studied in view of the effectiveness of emergency delivery. Adaptive traffic lights can be employed based on DSRC (Dedicated Short Range Communication) system, as vehicle status and traffic lights information can be delivered to Road Side Unit (RSU). In other research work of manipulating traffic lights, only the EmVs are considered. Therefore there are still risks for non-EmVs due to insufficient time of braking. This paper provides an adaptive traffic light control method which takes into account of EmVs and non-EmVs on all the directions of lanes at the road section. In this control method, three operation modes of traffic light are proposed and the traffic light can be converted among three operation modes: Normal mode, Warning mode and Priority mode. Moreover, a collision prediction of upcoming non-EmVs on the orthogonal lane of EmVs in the junction is performed, which results in non-EmVs protection within predefined distance to guarantee the safe mobility of no-EmVs in the orthogonal direction. Afterwards, the traffic light enters into Warning mode to provide a warning and buffering time for upcoming drivers. Then traffic lights turn into Priority mode until emergency vehicle leaves the junction. Before the traffic lights are back to the Normal mode, Warning mode is carried out again to ensure sufficient braking time for following non-EmVs in case of change of traffic lights. In a summary, this adaptive traffic light control method not only protects EmVs, but also improves the safe mobility of non-EmVs. Finally simulation is carried out and the results show that this method can greatly improve the efficiency and safety for EmVs and non-EmVs and reduce the accident rate in the junction.