Self-Control of Traffic Lights and Vehicle Flows in Urban Road Networks

摘要

Based on fluid-dynamic and many-particle (car-following) simulations oftraffic flows in (urban) networks, we study the problem of coordinatingincompatible traffic flows at intersections. Inspired by the observation ofself-organized oscillations of pedestrian flows at bottlenecks [D. Helbing andP. Moln\'ar, Phys. Eev. E 51 (1995) 4282--4286], we propose a self-organizationapproach to traffic light control. The problem can be treated as multi-agentproblem with interactions between vehicles and traffic lights. Specifically,our approach assumes a priority-based control of traffic lights by the vehicleflows themselves, taking into account short-sighted anticipation of vehicleflows and platoons. The considered local interactions lead to emergentcoordination patterns such as ``green waves'' and achieve an efficient,decentralized traffic light control. While the proposed self-control adaptsflexibly to local flow conditions and often leads to non-cyclical switchingpatterns with changing service sequences of different traffic flows, an almostperiodic service may evolve under certain conditions and suggests the existenceof a spontaneous synchronization of traffic lights despite the varying delaysdue to variable vehicle queues and travel times. The self-organized trafficlight control is based on an optimization and a stabilization rule, each ofwhich performs poorly at high utilizations of the road network, while theirproper combination reaches a superior performance. The result is a considerablereduction not only in the average travel times, but also of their variation.Similar control approaches could be applied to the coordination of logistic andproduction processes.