Optimizing Bus Transit Network By Using Strategy Equilibrium And Line Section Combination

Public transit network planning is a complex combinational optimization problem involving the analysis of travelling choice behavior, transit network design, optimization of departure frequency and assessment of transit network planning etc. The feasible bus line network can provide a comfortable and economical service for residents. A scientific network planning is significant for public transport to facilitate the operational efficiency.Based on the layout of urban regions, the level of traffic nodes and passenger travelling principles, this paper analyzes the bus-line characteristics and generates hierarchical bus-line segments divided by the central node. Then the paper proposes a model describing the process of bus-line segments composing bus lines. According to equilibrium model in frequency-based bus line network, the paper analyzes passenger travel choice behavior. Considering the interest of passengers and operators, a bi-level programming model on public transit network planning is established combining with the rational constraints of bus lines and bus network service constraints. In this model, the set of bus-line segments is a middle decision variable, and line set and departure frequency are final decision variables. The model can delete, extend or combine bus-line segments between a central node and a node in the service region but also delete, replace or add bus-line segments between central nodes even delete and generate bus lines between central nodes. These methods of bus-line adjustment and frequency-based trip assignment are used for neighborhood search in the simulated annealing algorithm. This algorithm solves the question about public transport network planning and the optimization of departure frequency. Finally, the paper reports an experiment in Sioux Falls to prove the efficiency of our optimal approach facilitating the social economy and service.