Research on design and optimum-method of double-layer urban transit network.

A new idea is put forward,which combines the transit skeleton-network with the transit feeder-network to establish the double-layer urban transit network.An optimization model of urban public transit skeleton-network is built and the genetic algorithm and the tabu search algorithm are designed respectively for the different layers.The calculating example shows that this algorithm has a good performance of searching,and it can provide a theoretical foundation for the planning and design of urban public transit network.