Modelling of emergency vehicle preemption systems using statecharts

Statechart has been utilized as a visual formalism for the modeling of complex systems. It illuminates the features on describing properties of causality and concurrency. This paper focuses on the use of statecharts to model the preemption of emergency vehicles system. The advantage of the proposed approach is the clear presentation of traffic lights´ behaviors in terms of conditions and events that cause the preemption phase. Moreover, the paper also proposes a new emergency vehicle preemption policy that provides the emergency vehicles can pass through the intersections with minimal delay. The analysis of the control models is performed to demonstrate how the models enforce the lights´ transitions by reachability tree method. And then the reachability and reversibility properties of the control statecharts will be obtained.