Research On Model And Algorithm For Static Traffic Assignment

Static traffic assignment is that the traffic demand is assigned on each path according to certain criterion. As the foundation of traffic planning, it can provide reference for the traffic managers and plays an important role in traffic management. A combination traffic distribution model is established in this thesis according to the characteristics of urban traffic in China. A new algorithm is proposed which can solve the general static traffic assignment models including the given combination model.In the traffic network with lots of origin-destinations(OD) those destinations having the same role, it is often the case that some destinations have too much traffic flow and the others have too little. In order to avoid this situation and make traffic distribution obey the arrangement of the traffic management as far as possible, this thesis establishes the combined model which satisfies the traffic mode choice, stochastic route choice and the doubly-constrained trip distribution. The premise conditions of this model are the fixed OD traffic flow and the symmetrical influence between different traffic modes. Then the feasibility of the model is given through its application to a simplify traffic network.Based on the characteristics of the constraint conditions in static traffic distribution models which contain linear equality constraints and linear inequality constraints, a new algorithm is given for solving these models. The algorithm doesn’t need any line search, and the direction is got by solving a simple quadratic programming problem. It greatly improves the computational efficiency. The algorithm shows availability for solving the general static traffic distribution models, such as user equilibrium model, system optimal model, combination model, stochastic user equilibrium model and so on. Furthermore, it has higher efficiency than MSA.