Study On Model And Demonstration Of Public Transit Priority Technology Strategy In Megalopolis

Urban transportation is an essential product of socioeconomic development and also one of the important basic infrastructures for the megalopolis existence. As an indispensable component of the urban dynamic system, it is a necessary material condition and basic industry for overall development of the megalopolis. Along with fast socioeconomic growth and change of travel ideas, contradiction between traffic demand and supply has seen a higher degree, such as increase of traffic congestion and accidents and increasing seriousness of environmental pollution caused by the traffic. So, to re-enforce development effort of megalopolis public transit and implement the strategy of "public transit priority" is an important measure to effectively solve megalopolis transport problems.The author made much investigation and research on the basis of long-term research and practice in urban public transit and finally confirmed the topic and study scope after repeated study and analysis as well as comparison:taking megalopolis public transit as study object, analyze main reasons for traffic congestion and then take research on technology strategy of public transit priority as study scope to conduct study on time priority and space priority of public transit. In this thesis creation, the author firstly reviews lots of reference and conducted research, and sums up the achievements and current development status of public transit priority strategy in the megalopolis both inland and abroad along with comprehensive interpretation of that. Based on this, the author then adopts the system engineering theory and methods, the systematic approach, the qualitative and quantitative analysis method, the Petri net theory, Dempster-Shafer Theory and Catastrophe Theory to conduct research on graphical model of large city ground public transit priority technology strategy, and then structures that on the basis of Petri net Theory; next, on the basis of Dempster-Shafer Theory and Catastrophe Theory, the author conducts a comprehensive evaluation of the megalopolis public transit priority technology strategy and constructs comprehensive evaluating index and sub-index with qualitative and quantitative drawn into the same model for the sake of evaluation; finally, the author puts forward suggestions on adjustment and optimization of public transit network by taking public transit network in Beijing as empirical study. Based on the studies of the predecessors, the author has achieved the following innovative results:1.On the basis of system engineering theory and method, the traffic system of major cities in our country is analyzed. In particular, the technical tactic on developing traffic system of major cities is systematically analyzed and studied. Then by combining qualitative analysis and quantitative analysis and through comprehensive evaluation of the public transport priority systems, the argument is made that developing public transport is an essential way to solve urban traffic problems.2.The megalopolis public transit priority technology strategy is established on the basis of the theory of Petri net together with domestic megalopolis ground public transit priority technology strategy. The Petri net has the advantages of parallel travel, concurrent dispatch and synchronization. Through modeling method of Petri net, the whole process of transit with time and space priority in the megalopolis ground public transit priority strategy is depicted and analyzed. By dividing the transition into timed transition and immediate transition and adopting the inhibitor arcs and the priority given to each arc, the megalopolis ground public transit priority GSPN model, which represents the principle of public transit priority, has been established. In addition, the mathematical method is used to analyze the performance indices of the system and the existing public transit priority technology strategy is compared with non-public one so as to achieve an effective strategy on public transit priority system, thus laying a theoretical basis for realizing public transit priority. Besides, specific measures and methods to achieve efficiency of public transit priority are also brought up.3.In the comprehensive evaluation methods of the megalopolis public transit priority system, by adopting the Dempster-Shafer Theory and the Catastrophe Theory, the author puts forward a quantitative comprehensive evaluation method based on Dempster-Shafer Theory and Catastrophe Theory. By repeated comparison, discussion and consulting relevant experts, evaluating index and sub-index for megalopolis public transit quantitative priority are determined. Then, the comprehensive evaluation method of the public transit network is determined in accordance with the importance of the indices and the sub-indices and with combination of specialist reliability. For different experience and preference from different experts, Dempster-Shafer Theory composition rule is used to combine the probability assignment of evaluation index by integrating evaluations of different experts to get evaluation value of sub-index and then by adopting Catastrophe Theory, take evaluation index and sub-index as control variables to comprehensively evaluate public transit priority system, thus avoiding the subjectivity of artificial decision. The cases demonstrate that the method is feasible.4.Based on the study on effectiveness of public transit technology strategy by taking ground public transit network in Beijing as instance as well analysis of the existing public transit network, public bus lane (BRT) and transportation hub, the author has proposed the objective and measures for improving the existing public transit network.