Hybrid petri net modeling of traffic flow and signal control

Traffic control systems of signalized intersections are naturally hybrid systems, in which vehicle flow behavior can be described by a time-driven model and the traffic light dynamics are modeled as a discrete event system. In this paper, we use hybrid Petri nets (HPNs) to specify traffic and traffic control at an intersection and use a second-order macroscopic model to model the motion of vehicles in a road stretch between two successive intersections. The traffic control system of an arterial street is thus modeled as a composition of individual intersection models and road stretch models. Such a structure is suitable to perform traffic optimization by changing the length of the offset between two adjacent intersections with the common cycle.