Determining optimum configuration of one-way and two-way streets using shortest path travel costs based on results of traffic assignment

Abstract

Traffic congestion is one of the major problems in transportation field. To reduce unfavorable impact of that problem, one of the conventional applications is to find optimal or near-optimal configuration of one-way streets on road networks. When some of two-way streets in the network are converted to one-way, which may be cheaper than other possible improvements, the performance of the road system may increase. Thus, this arrangement should be evaluated in order to determine its possible effects. For this purpose, a bilevel heuristic solution algorithm is proposed to find optimal configuration of one-way streets on road networks in this study. The upper level deals with finding optimal configuration of one-way streets by minimizing the total flow (demand) weighted shortest path travel costs (distance) while user equilibrium link flows are determined in the lower level. Shortest path travel costs between OD pairs are obtained after executing traffic assignment module of VISUM software by considering link travel times according to created network configuration in the upper level. To make more attractive one-way streets, we have used the parameter of a which is multiplied with the length of one-way streets to increase its speed. The bilevel heuristic solution algorithm is combined with VISUM and applied to Sioux-Falls city network. The results of near-optimal arrangement of one-way streets are compared with those of base case in terms of objective function considered. Additionally, sensitivity analysis was performed to investigate how the algorithm reacts to the variation of the parameter of a. Results showed that developed algorithm may be considered for finding optimal configuration of one-way streets on urban road networks.