Generating More Equitable Traffic Signal Timing Plans

Abstract

Signal timing plans designed under a total delay minimization strategy can induce excessively high delays for low-volume movements and result in an uneven distribution of delay among motorists. A multiobjective optimization approach is considered for the minimization of both overall delay and delay imbalance. The multiobjective method is found to be highly successful. Compared with a pure delay minimization strategy, the multiobjective optimizer is able to produce signal timing plans with similar overall delay that have a considerably more equitable delay distribution. Multi-objective optimization provides the traffic engineer with a choice from an entire range of compromise solutions in the two competing objectives. Large reductions in the delay imbalance can be achieved at the cost of small sacrifices in overall delay. Multiphase signal control, shifting green splits in favor of low-volume movements, and decreasing bandwidth provide more-balanced delays at the cost of increasing overall delay.