Real time control of critical intersections based on queue dynamics

Several control schemes have been proposed in the past for optimal control of congested intersections but they have not been applied in real life situations partly because of the complex instrumentation required for their application and partly because they do not combine all control objectives at such intersections. Open and closed loop control policies minimizing total intersection delays subject to queue size constraints have also been proposed by the authors. All control policies, however, have the disadvantage that they are based on simple traffic models describing the effective size of the queues rather than the queue lengths. In this paper a new model is presented describing the queue dynamics at signalized intersections as a function of the demands, the intersection characteristics and the control decisions. A control policy combining the results of this model and control principles previously developed by the authors is also proposed.