Heuristic algorithms for capacity flexibility of urban transit networks

In this paper, the concept of capacity flexibility is introduced into transit network, and the model of capacity flexibility of urban transit networks is formulated. A heuristic solution based on hybrid genetic algorithm is proposed to the model. GA-LS (Genetic algorithms with Local search) is applied to solve the model. It is also tested by a numerical example with a small transit network. The results show how the maximum additional passenger flows from each origin-destination (OD) pair are determined in a transit network and what extent the transit network supply meets the additional passenger demand in a certain level of service. These results show that the GA-LS method considerably improves the value of the objective function for same iterative times compared with the general GA, but spending more time.