The effects of anticipatory traffic control for several small networks

In this paper the integrated traffic control and traffic assignment problem is studied. This problem can be considered as a non-cooperative game in which the traffic authority, that controls the traffic signals, and the road users are the players, who use their own strategy and seek their own optimum. The game theoretical formulation leads to several different control strategies in which users' reactions to traffic control decisions are taken into account. Users' reactions can be the choice of route, departure time or even mode. In this paper some of these control strategies for traffic signal control are described: Webster control, Smith's P0, local control using genetic algorithms, anticipatory control and system optimum control. The anticipatory control strategy can be formulated as a bi-level optimisation problem and this problem is solved using genetic algorithms. Also the system optimum solution can be found using genetic algorithms, simultaneously optimising route flows and green times. In the paper the assignment method, together with the traffic model are formulated. For several simple example networks the traffic control methods are tested and it is shown that taking route choice into account is beneficial to the network performance. One of the examples includes ramp metering in its simplest form and can be considered as an example of integrated control. Further research will focus on larger networks, the use of microscopic simulation and the problem of departure time choice.