Context-aware traffic light self-scheduling algorithm for intelligent transportation systems

Traffic lights are located on the road intersections to control and manage the competing traffic flows. Several algorithms have been proposed considering the real-time traffic characteristics of each competing traffic flow at the road intersection. Emergency vehicles such as ambulance, fire truck and police vans should have higher priorities to cross any road intersection first. Whenever an emergency vehicle appears close to any road intersection, all vehicles on the competing flows should stop and allow that vehicle to proceed first. However, this may cause a hazards situation in the case that any driver miss-behaves or insists to follow the current traffic light phase. In this paper, we aim at designing a context-aware traffic light self-scheduling (CA-TLS) algorithm. This algorithm uses the traffic characteristics of the traffic flows and the emergency vehicles presence on the competing flows at any signalized road intersection. First, these parameters are gathered using periodic advertisement messages of traveling vehicles. Then, the CA-TLS algorithm sets the phases of each traffic light cycle according to the traffic gathered data. The green phase of any traffic flow can be interrupted to enable the fast proceeding of the appeared emergency vehicles. An extensive set of experiments have shown that this algorithm decreases the delay time of emergency vehicles at the signalized road intersections.