Urban Travel Mode Split Optimization Based On Travel Costs

With the rapid development of economy and accelerated pace of urbanization in China, mode splits of some urban transportation systems bring out a serious imbalance. The research investigates the optimal mode-split for a developing megacity considering travel costs of different modes, to improve the system developing sustainability. Based on the generalized travel cost (GTC) per capita for one trip for each mode on an urban transport network, the weighted GTC per capita for one trip optimization model combined with the Nest-Logit (NL) model is established. In addition, the research analyses the effect of different optimization schemes in the case study so as to provide a basis for obtaining the reasonable mode-split, reducing the travel cost, and achieving sustainable development of the urban transportation system.Firstly, the researches about discrete choice model, travel optimization modeling and optimization schemes are reviewed based on the mode-split modeling, travel optimization methods and optimization policies.Secondly, the research regards the main urban area of Beijing as the study area, and details the GTC per capita for one trip on an urban transport network. Then, NL model is developed to describe the mode-split of urban transport. Then, the comprehensive GTC per capita for one trip optimization model is constructed. The comprehensive GTC per capita for one trip consists of time cost and monetary cost per capita for one trip. Considering the algorithm design, genetic algorithm (GA) is used to solve the constructed model.Finally, different cases are studied for the analysis of the effect of different transport policies These policies are concerned with parking fee of private car, taxi average fare, bus in-vehicle time saving, rail transfer and waiting time saving individually, and policy package which combines four policies. It is found that the policy for reducing the bus in-vehicle time has the greatest effect on reducing the comprehensive GTC per capita for one trip on the urban transport network. And the policy package can achieve the mode-split effective optimization and the developing sustainability of urban transport system by way of reducing the travel cost on the transport network comprehensively.