Numerical Simulation, Analysis Of Characteristics Of Phase Transition And Application For Traffic Flow

With the development of social economy, traffic problems have become bottlenecks to restrict the development of cities. The developments of economy and society, even society stabilization, have been influenced strongly by traffic jam, traffic pollution and traffic accidents. In order to solve the traffic problems better, most carried out a lot of traffic investigations and empirical measures and found various traffic phenomena. Many mathematical models have been proposed for the transportation prediction, management and planning.In this thesis, by using theoretical analysis and numerical simulation, we study the characteristics of phase transition of cellular automaton models and the application of traffic flow hydrodynamic model to solve the traffic jam problems. The contents of the thesis are as follows(1) Based on the BJH model of traffic flow, a new evolution algorithm of traffic flow by considering the effects of the braking state of vehicle ahead on traffic flow is proposed. The fundamental diagram obtained by numerical simulation shows higher the capacity of road, which approaches to the empirical data. Moreover, the model is able to reproduce the complicated behavior of the real traffic, such as capacity drop.(2) By computing the spatial correlation function, the evolution plots of velocity, the relaxation time and the order parameter, the effect of top-priority of randomization on traffic flow is studied. The scaling relations and the scaling exponents of the relaxation time and order parameter are obtained, which are different from original NaSch model. The top-priority of randomization will lead to synchronized traffic flow and there is criticality in traffic phase transition. The scaling exponents of relaxation time is similar to those of deterministic NaSch model.