Traffic Flow Modelling And Traffic Status Analysis For City Road Network

Reasonably accurate mathematical modelling of traffic flow is essentially important not only for better understanding of the collective behaviour of traffic, but also for analyzing flow conditions, designing efficient control strategies, and etc. Over the past decades, many researchers with different background had made intensive studies on this subject and a wide range of traffic flow theories and models had been developed. In this dissertation, based on the existing microscopic models for traffic flow, several improved mathematical models are presented, and the corresponding theoretical analysis and numerical simulation are conducted. Moreover, the application research of macroscopic traffic flow model has been used in city road network of Shanghai with the real-time data collected by under-ground detecting loops of SCATS system. The major contributes of the thesis are as follows.1. We propose two improved car-following models of nearest-neighbor interaction: the adaptive headway model and the velocity-difference-separation model. In the first modified model, a new nonlinear term, which attempts to adjust the inter-vehicle spacing to a certain desired value, is proposed to overcome some deficiencies in the GHR model. In the velocity-difference-separation model of car-following, we think the model should make allowance of the effect of the inter-car spacing independently of the relative velocity. The improvement of this model over the previous one lies in that it not only theoretically retains many strong points of the previous ones, but also performs more realistically than others in the dynamical evolution of congestion in the coexisting phase. Numerical results prove the two modified models are more useful and reasonable in many applications.