Comparison of Two Approaches for Preemptive Traffic Light Control

By implementing preemptive traffic light control systems in urban areas it is possible to reduce the travel time of specific groups of vehicles such as emergency vehicles. In this paper, two approaches for preemptive traffic light control are compared by applying a microscopic simulation model. The first approach uses fixed values of vehicle arrival time and queue lengths thresholds while the second is fuzzy logic based and hence more adaptive. Both approaches are tested in six different scenarios with an use case consisting of a simulated isolated intersection based on real traffic data. Analysis of the results shows that the travel time of emergency vehicles can be reduced by up to 24 % in heavily congested conditions with a slight edge given to the fuzzy logic based approach. Both approaches show negligible negative effects on the total travel times of all vehicles in the network.