Research On Key Problems Of Public Transport System Structure In Mega-City

On one hand, the reality determines that Chinese megacities are bound to develop urban public transport system as the fundamental mode in the urban transport infrastructure. On the other hand, there are many practical difficulties and development errors in the process of the development of urban public transport system in Chinese megacities. One of the most significant reasons goes to that the absence of thorough analysis to the key problems of structure behind the urban public transport system itself, which can be mainly divided into three categories that include land use, travel demand and supply configuration.Therefore, this paper studies the key problems of structure behind the urban public transport system in Chinese megacities under the research framework of public transport system structure, which is based on the perspectives of land use optimization based on transit, transit demand analysis and coordinative optimization of transit configuration. The main target of this paper is to reveal and tackle the key problems of structure behind the urban public transport system in Chinese megacities, and to achieve the strategic objectives of prioritizing urban public transport development. This paper includes the following research:(1) Firstly, the key problems of this paper are clarified, and the domestic and international research is reviewed. The cases of domestic and foreign urban public transportation system development are described, and the relevant definitions of urban public transport systems are clearly stated, which point out that the public transport system structure should contain both public transport demand structure and configuration structure, besides the public transport mode structure.(2) The land use optimization based on transit is studied. This chapter is in response to the structure problem of "uniform distribution" of land use density. Firstly, to determine the mode of development of public transport and land use, the differential equation model is constructed to analyze the stability of the interaction between public transport and land use. Secondly, to reveal the uneven spatial distribution of the land use values around constructing URRT, the bi-level regression hedonic price model (BLR-HPM) is built, which can be the economic basis of the uneven spatial distribution of land use density. Thirdly, compound optimization model between public transportation and land use density is studied, taking the maximum of the welfares of public transport agencies and travelers as two objectives, the bi-level optimization model is built.(3) The transit demand analysis based on land use is studied. This chapter is in response to the structure problem of "uniform input" of land use influence factors of transit demand analysis, which ignore the fact of the uneven spatial distribution of transit demand. Firstly, by using structural equation model (SEM), the quantitative effects between the distances to public transport stations and the travel behavior which including travel distance, time and frequency are revealed. Secondly, taking urban rapid rail transit (URRT) as example, the direct ridership model of urban rail transit stations based on spatial weighted LS-SVM is proposed. The results show the model improves forecast accuracy and simplifies the model data demand, and can improve the model reliability as a supplementary model of public transport demand forecast.(4) The transit demand analysis based on trip chain is studied. This chapter is in response to the structure problem of "simplification" in analyzing the course of trip in transit demand analysis, which does not match the real course of trip. Firstly, the entropy-maximizing (EM) model of trip chain in multi-modal transport network is proposed, whose results show that the model fit well with real values in the 5 benchmark indexes, which indicate the validity of the model. Secondly, to study the URRT trip mode chain, the Cross Nested Logit (CNL) model of joint selection is built. These two models may provide a comprehensive and effective modeling tool to analyze the urban transport trip, which are closer to the real course of trip and having higher explanatory power.(5) The coordinative optimization of the public transport system configuration is studied. This chapter is in response to the structure problem of focusing on the pursuit of a certain kind of public transport mode. Firstly, the different versions of the overall layout of public transport system configuration are stated. Secondly, different characteristics of various major modes of public transport are described. Thirdly, the bi-level optimization model for bus network considering the accordance with the URRT is established, whose results are assigned into the real urban transportation network by using traffic modeling software which achieve a better effect.