Study On The Robust Traffic Assignment Under Interval Demand

Transportation system is a very complicated system, containing all kinds of uncertainty, especially the uncertainty of traffic demand, which leads to the uncertainty of the traffic impedance on the road. So that it is difficult for the traveler to make route choice, which finally leads to the traffic allocated on the road network also containing a great deal of uncertainty. However, traffic demand is the basis of traffic assignment, and traffic assignment is a very important link of traffic planning, so correctly or not of the traffic assignment results are directly related to the stand or fall of road network planning scheme. Therefore, only by fully considering the uncertainty of traffic demand and getting the results of traffic assignment under uncertain traffic demand, making road network planning on this foundation, can we make a better effect on improving the ability to resist risk of the road network to be planned.This thesis gives full consideration to the uncertainty of traffic demand and the robustness of routing, adopts reasonable range of interval number to measure the traffic demand, defines the robust path cost on the basis of interval networks, and thus the robust shortest path model is established, at the same time puts forward the effective solving algorithm; then defines the robust and effective path and discusses the user equilibrium conditions under the interval traffic demands on the basis of the robust shortest path, establishes the robust multi-path assignment model and the user equilibrium assignment model under the interval traffic demand, and designs the corresponding algorithm for the respective model. Finally this thesis describes a simple network example, using computer software to get the solution of the example, at the same time, respectively, compares and analysises the results with the results of the deterministic model, the results show that the model and algorithm proposed in this thesis is reasonable and effective.The calculations of robust traffic assignment model under interval demand are interval number, which contain uncertainty information and provide a good basis for the next stage of the road network planning decision-making. They can also reduce the risk of decision-making effectively, thereby enhance robustness of the road network and the ability to resist the risk.