Unified Evaluation Method for Traffic Control Algorithms

Abstract

Traffic lights play a major role in traffic management. It is known how to compute the delay-minimizing optimal programs for single intersections or networks of them, if a static flow is assumed. But traffic flow changes on different time scales and many adaptive algorithms were developed, all of which adapt the green time durations, phase orders, and cycle lengths to the current traffic state. Evaluation of these more advanced traffic light control algorithms is more complex. The perfect control strategy is not known, so a comparison with a ground-truth is not possible. In literature many different metrics are used to evaluate the algorithms, but none of them are complete and they are difficult to compare with each other. This paper will derive a unified evaluation method for traffic control algorithms. As a first step a complete set of metrics with minimal overlap is determined. This set will include users’ perception, which is currently not used in literature to evaluate control algorithms, but shows significant added value. The second and last step is combining the metrics into one final criterion for evaluation by using a policy based scheme.