Design of signal timing plan for urban signalized networks including left turn prohibition

Abstract

Urban road networks may bene�t from left turn prohibition at signalized intersections in terms of safety and capacity, for particular tra�c demand patterns. The objective of this paper is to propose a method for minimizing the total travel time by prohibiting left turns at intersections. The �nal output is a list of the prohibited left turns in the network, and a new signal timing plan for every intersection. Using the ows obtained from the stochastic user equilibrium model, we were able to derive the stage generation, stage sequence, cycle length and the green duration of each stage. The optimal list of prohibited left turns was found using the genetic algorithm, and a combination of several algorithms was employed for the signal timing plan using a stage-based method. The results show that left turn prohibition may sometimes lead to travel time reduction. Therefore, when designing a signal timing plan, left turn prohibition should be considered just as any other left turn treatment.