An Urban Intersection Traffic Flow Model Based On Multi-commodity Kinematic Wave Theories

Traffic flow models of urban intersections can be used to evaluate their performances and offer a base for traffic control strategies design, road networks design, and so on. The complex conflicts among traffic streams at urban intersections, including zero conflicts (i.e., no conflict), merging conflicts, diverging conflicts and crossing conflicts, have not been synthetically modeled by existing models. In this paper, we consider the central district of a four-leg urban intersection as a 2x2 grid matrix and present a new traffic flow model of urban intersections based on multi-commodity discrete kinematic wave (MCDKW) model. In this model, we use a fair merging rule and both strictly First-In-First-Out (FIFO) and non-strictly FIFO diverging rules. The model is used to jointly simulate the aforementioned four kinds of conflicts at an un-signalized urban intersection. Different scenarios are designed in simulation and it is obtained that the intersection capacities corresponding to different commodity groups are varied. Moreover the model is used to simulate conflicts at a signalized urban intersection, where there are no crossing conflicts. As a result, the recurrence of gridlock occurred at un-signalized case is prevented.