“…Later on, Tzes, et al (1996), Gallego, Farges and Henry (1996) and Di Febbraro, Giglio and Sacco (2002) have modelled traffic lights controlling TNs by PNs: these approaches share the idea to adjust signals controlling an intersection according to the distinct tokens deposited in a PN controller. More recently, List and Cetin (2004) discuss the use of PNs in modelling traffic signal controls and perform a structural analysis of the control PN model by P-invariants, demonstrating how such a model enforces the traffic operation safety rules. With particular reference to the use of PNs for modelling TNs, Di Febbraro, et al (2002) present a traffic model in a timed PN framework, where tokens are vehicles and places are parts of lanes and intersections.…”