Performance Analysis of Isolated Intersection Traffic Signals
Kai Yin, October 2013
This dissertation analyzes two unsolved problems to fulfill the gap in the literature: (1). What is the
vehicle delay and intersection capacity considering left-turn traffic at a pre-timed signal? (2). What are the mean and variance of delay to vehicles at a vehicle-actuated signal?
The first part of this research evaluates the intersection performance in terms of capacity and delay at an isolated pre-timed signal intersection. Despite of a large body of literature on pre-timed signals, few studies have examined the interactions between left-turn and through vehicles. In order to examine this missing part of study on the signalized intersection, two probabilistic models are proposed to deal with the left-turn bay blockage and queue spillback in a heuristic manner. The second part of this research studies an isolated intersection with vehicle-actuated signal. The actuated system dynamically allocates the green time among multiple approaches according to vehicle arrivals. We develop a model to study the vehicle delay under a general arrival distribution with a given unit extension. The model allows optimizing the signal performance over the unit extension. The third part of this research applies graphical methods and diffusion approximations to the traffic signal problems. We reinterpret a graphical method originally proposed by Newell in order to directly measure the variance of the time for the queue clearance at a signalized intersection. Furthermore, we investigate the problems of disruptions occurred during a pretimed traffic signal cycle. By diffusion approximation, we provide the quantitative estimation of the duration that the effects of disruptions dissipate.
Keywords: Traffic Signal, Isolated Intersection, Left-turn Traffic, Actuated Signal, Graphical Methods, Diffusion Approximation
ENTIRE DISSERTATION (Adobe Acrobat File – 18.5 MB)