A Flow-adjustment-based Heuristic Algorithm For Traffic Network Assignment Problem

The algorithm of traffic assignment problem falls within the category of optimization algorithms.Designing the algorithm of traffic assignment problem on the basis of flow-adjustment mechanism is different from classical optimization algorithms.From the characteristics of the equilibrium problem,this paper proposes a new flow-adjustment-based algorithm for traffic assignment problem,which is an extension of the existing heuristic algorithm for traffic assignment problem.Chapter 1briefly introduces the background of traffic assignment problem with the corresponding classic models and algorithms.Chapter 2 introduces the new progress of traffic assignment models and algorithms.Also,the traffic assignment problem based on flow-adjustment mechanism is reviewed in detail.Chapter 3 proposes the new flow-adjustment-based algorithm for traffic assignment problem.In this algorithm,a perturbation rule is presented for solving the least squares problem so as to obtain an search direction for current iteration.It can not only guarantee the feasibility of current iteration on path flows,but also have the potential for saving the computational time of the algorithm.Then,the new flow-adjustment-based algorithm of the traffic assignment problem is presented.This algorithm also satisfies the properties of the original heuristic algorithm for traffic assignment problem.Finally,numerical examples are presented to demonstrate that the perturbation rule can not only guarantee the convergence of the algorithm,but also save the computational time.Chapter 4 applies the proposed algorithm for network design problem.The results of an medium-scale transportation network showed that the proposed algorithm can saves 10.4% of computational time than the original one in the network design problem.Conclusions and the further studies are presented in chapter 5.