An Evaluation of Flyover-Improved Intersections: A Case Study of Airport Intersection

Abstract

A flyover over an existing at-grade intersection is constructed to reduce traffic congestion. However, under the flyover which has been shown to help relieve traffic congestion at the intersection, the traffic signal control still uses the same control method as the “before” situation; that is the fixed time control plan. After the installation of the flyover, it was found that about 45% of traffic diverted to it, the time delay reduced by 34% over the same period. The economic evaluation results show that the net present value equals 361.64 million baht, benefit cost ratio, 1.34 and internal rate of return, 37.58 percent. The paper describes economic benefits of the flyover and presents the performance of the flyover improved intersection and points out the remaining problems under the flyover. Suggestions for improving performance of the existing traffic signal are made using results from SIDRA software.