Abstract: To improve the direct rate of transit network on the basis of transfer demand satisfied with the least transfer, a direct transit network optimization model with the goal of maximizing the direct rate and minimizing the total direct time was designed. Minimizing transfer times was discussed as constraint in the model compared with the existing research, and meta-heuristics algorithm that utilizes main operators similar to GA was applied for solutions. Floyd algorithm was used to find the shortest path of the initial transit network as initial transit network by decreasing routes or combining routes, so that the model obtained initial solution of high quality. Total transfer times of transit network was calculated by space P method, and minimizing transfer times was taken into account under the existing constraint conditions that contains frequencies, fleet size available, length of transit routes, and so forth, and then the demand was distributed to routes using frequency share rule. Comparing with the existing research results, the results show that the direct rate increases by 9.7%, 8.41% and 0.39% in the Mandall's Swiss network of four routes, compared with the experiment 1, 2 and 3 of the existing research without considering the optimization of frequencies.

Key words: transit network optimization, direct transit network, meta-heuristics algorithm, minimizing transfer times constraint, initial transit network