HEURISTIC PROGRAMMING APPROACH TO ARTERIAL SIGNAL TIMING

A heuristic programming approach to minimum-delay arterial street signal timing plan optimization is presented. The selection of a good heuristic solution for phasing sequence, cycle length, and green splits is demonstrated. The approach demonstrates a procedure for use by the traffic engineer in selecting the phase sequence, cycle length, and offsets for an arterial street for developing a minimum-delay signal timing plan from existing computer programs. The heuristic procedure is to use the PASSER II computer program for maximum bandwidth progression optimization to select the phasing sequence and the initial starting point for use in the TRANSYT 6 computer program to develop a minimum-delay performance index solution. This permits all signal timing variables to be optimized. Comparisons are made between this heuristic solution and the best signal timing plan developed (considering all possible combinations a priori) by the TRANSYT program. An evaluation of use of the PASSER II green split routine versus the TRANSYTSTAR1 routine on the program solution was performed. The heuristic procedure, when restricted to the minimum-delay cycle length, resulted in at least a good solution versus a TRANSYT best solution that used a measure index. A comparison of the PASSER II green splits and the TRANSYTSTAR1 routine produced mixed results.