We study the impact of global traffic light control strategies in a recentlyproposed cellular automaton model for vehicular traffic in city networks. Themodel combines basic ideas of the Biham-Middleton-Levine model for city trafficand the Nagel-Schreckenberg model for highway traffic. The city network has asimple square lattice geometry. All streets and intersections are treatedequally, i.e., there are no dominant streets. Starting from a simplesynchronized strategy we show that the capacity of the network strongly dependson the cycle times of the traffic lights. Moreover we point out that theoptimal time periods are determined by the geometric characteristics of thenetwork, i.e., the distance between the intersections. In the case ofsynchronized traffic lights the derivation of the optimal cycle times in thenetwork can be reduced to a simpler problem, the flow optimization of a singlestreet with one traffic light operating as a bottleneck. In order to obtain anenhanced throughput in the model improved global strategies are tested, e.g.,green wave and random switching strategies, which lead to surprising results.
展开▼
