Application of Search Methods to Optimization of Traffic Signal Timings in Traffic Flow Model in TRANSYT

Abstract

TRANSYT (A Traffic Network Study Tool) is the most representative and practical simulator for the optimization of such control parameters as cycle length, split and offset in road network. The problem with TRANSYT is that the calculated solution using a hill-climbing method has not necessarily insured the optimum value because it can be found by searching for combinations of distributed variables. Further, it depends on the initial values set as the starting point in searching. This paper describes new approaches for the simulator for optimizing control parameters, in which situations from non congested to oversaturated traffic conditions can be treated. The optimization problem is represented by string model and this formulation enables to introduce such search methods as random search, genetic algorithm and simulated annealing. The experiments which were carried out to verify the usefulness showed that they are superior to the conventional method used in TRANSYT regarding convergency and optimality of solution.