Signal timing design of malformed intersections based on the change of road cross angle

Abstract

In urban road systems, malformed intersections are one of the pain points. And their unreasonable signal timing is a major contributor to issues such as low intersection capacity and high safety risks. This paper uses the Webster model to investigate the relationship between intersection angle, driving path and stopping sight distance, considers the impact of road intersection angle on lost time and saturation flow, and proposes a signal timing optimization method for malformed intersections based on the change of road intersection angle. The article takes a malformed intersection of South Tai Bai Rd in Xi’an, Shaanxi Province, as an example, and gives a signal timing optimization scheme using Synchro, while VISSIM is adopted to verify the effect of the signal timing optimization scheme. The results show that compared with the conventional signal timing model, the overall average queue length of the intersection is reduced by 18.74%, the average vehicle delay is reduced by 1.82%, the number of stops is reduced by 22.93%, the level of service of intersection is improved from E to D, and the overall traffic operation efficiency is significantly improved by using the model developed in this paper. The research results are of great practical and guiding significance to alleviate congestion at malformed intersections and improve intersection traffic safety and efficiency.