Research On Dynamic Model Of Mixed Traffic Flow

Traffic flow theory is a frontier subject that describes the characteristic and formation mechanism of traffic, and traffic flow model is the important method which is used to simplify the analysis of traffic flow and assessment of traffic control strategies including road network planning and designing, traffic management and so on, which can provide traffic managers and users with theoretical foundation. However, in China, it is not practical to apply the same theory and method on car flow using in the developed countries because of our specific mixed traffic flow. Therefore, it is important to indicate the formation mechanism of the traffic flow between with different vechicle styles, build mixed traffic flow model by dynamics, control the traffic system, and improve the worsening traffic congestion situation the traffic status according to the nature of the mixed traffic flow in China. So, this work not only has important theoretical significance, but also has practical significance.The paper sets up the traffic flow model by means of dynamics for different vehicle types, based on the study of continuous traffic flow model. The main work includes model derivation, parameter calibration, discretization of model, performance analysis of model and effectiveness verification. Details are as following.First, after introducing the study status of traffic flow theory in China and developed coutried, analyzing the first-order and high-order traffic flow models, the thesis pointes out that the characteristics of the existing traffic flow model and problems which demanded prompt solution perfectly, and summs up the basic relationship of parameters and commonly numerical methods. Then the composition of traffic flow, traffic characteristics, traffic flow classification, the formation of mixed traffic flow and traffic flow basic features are described.Analyzing the derivation process of the traditional car-following model, summing up the previous work, the simplified term in the traditional car-following model is defined as the interference between vehicles, which is the viscous term in high-order traffic flow model. And a new car-following model, new speed-density function and relaxation time function are presented; the new high-order continuous traffic flow model is set up by dynamics; then, the upwind difference numerical solution and Lax difference numerical solution are given. Paper provides an optimization procedure for calibration of the model parameters.Paper analyzes the mathematical properties and performance of the new model, the analysis conclusion shows that the new model can solve the following problems in theory, which include:eigenvalue problem, the negative speed problem, the linear stability, discontinuous transmission, dissipation of congestion, the transmission and state conversion of cluster. And these issues once plagued most of the existing high-order models.Then, paper redefines the traffic congestion level, and defines a dimensionless parameter to quantify the traffic congestion level. And the traffic congestion level model is set up, which takes into account the proportion of vehicle types, traffic conditions, traffic environment, and other factors. According to the size of the congestion level, the traffic state is divided into five kinds. And the experiments confirm that the model can descript the traffic status really, objectively, moreover, the model has no restrictions on use.Finally, paper designs several experiments to test the validation of new model in qualitative and quantitative.