Performance Evaluation of Signalized Urban Intersections under Mixed Traffic Conditions by Gray System Theory

This paper presents a gray system theory-based method for the quantitative evaluation and ranking of the operational and safety performance of signalized intersections in urban areas under mixed traffic conditions. Mixed traffic conditions refer to traffic situations in which motor vehicles, bicycles, and pedestrians share a signalized intersection. Such mixed traffic is a typical phenomenon in many cities around the world in which the populations of urban areas are extremely large. Five index parameters are used in the proposed method: the degree of saturation, the average stopped delay, the queue length, the conflict ratio, and the separation ratio. These parameters represent the operational and safety performance of a signalized intersection with mixed traffic. They are inputted into the evaluation equations, which are developed according to the gray system theory. The method is applied to the performance evaluation of the intersections and network in the urban area of Changsha, China. The results show that the method can be used to conduct a comprehensive performance evaluation and ranking of signalized intersections under the mixed traffic conditions that are associated with urban road network systems.