Link Transmission Graph Model Of Urban Traffic Network: Modeling, Analysis And Simulation

The thesis focuses on the study of urban road traffic networks. On the basis ofanalyzing the structure and characteristics of the road networks, a macroscopic trafficflow model named Link Transmission Graph Model is proposed for modeling theroad network traffic flows. Based on the model, the thesis studies several controlstrategies and their performance evaluations, and makes experiments for a practicalroad network in Beijing. The main researches and their contribution are as follows.First of all, Link Transmission Graph Model is proposed. In the model, the roadnetwork is decomposed into basic units (sections or links of the road) in accordancewith the transmission of the traffic flow, dynamic directed graph is used to describethe topology of the traffic network, and then the Cell Transmission Model (CTM) isextended by introducing queue lengths into the model to describe the transmission oftraffic flow. The introduction of the queue length avoids the constraint of equal lengthof cells in CTM and improves the accuracy of the model, and more over it is moreeffective for traffic signal control.Next, based on the Link Transmission Graph Model, the thesis studies severalsignal control strategies of road networks, including the fixed timing control strategy,emptying switching control strategy and the oscillator network synchronizationcontrol strategy. The fixed timing control strategy is often used in practice. In theemptying switching control strategy the traffic signal control is considered as aswitching service system, and then the cycle of traffic control is calculated by thestability theory of the switching service system. In the oscillator networksynchronization control strategy the traffic control is regarded as the cyclical motionof the oscillator, and the coordinated control of intersections is seen as thesynchronization process of the oscillators, and thus the cycle and phase difference oftraffic control is obtained.Thirdly, new performance evaluation indexes of the control strategies areproposed. Based on the analysis of the existing traffic evaluation indexes of the trafficnetwork, the thesis constructs the three levels evaluation system which is from thelocal level to the global level, and evaluates the traffic from the three levels of roadsection, intersection and regional network. Finally, the thesis constructs a macroscopic traffic control simulation softwarefor the Link Transmission Graph Model, traffic control strategy and traffic evaluationsystem, and then uses it to model and control a small real traffic network.The thesis finally summarizes the research work, and proposed the furtherproblems which we need to research.