Analysis Of Coordination Mechanism And Evaluation Of Coordination Degree Between Rail Transit And Urban Morphology

With the development of urbanization in China,the daily travel demand of residents is increasing,and the urban traffic problems are gradually prominent.Rail transit has the advantages of high speed,large volume of traffic and less demand for road resources.It is of great significance to improve the sharing rate of urban public transportation and alleviate the existing traffic problems,so it has rapidly become the focus of the construction of major cities.However,as a large-scale municipal infrastructure project,the traffic demand should be reasonably predicted according to the spatial layout,population distribution and other urban morphological characteristics in the preliminary planning,so as to provide stable and sufficient passenger flow support for rail transit operation and avoid the negative impact of unreasonable rail transit construction on the healthy development of the city.In order to clarify the interaction mechanism between rail transit and urban morphology,the paper first put forward the idea of analyzing the coordination mechanism with the method of system dynamics.Starting with the internal elements and relevant policies of the rail transit and urban morphology system,the system boundary was determined and the causal relationship was analyzed,the system dynamics model of rail transit and urban morphology was constructed,and the qualitative causal relationship and quantitative flow stock were studied.The system coordination mechanism was analyzed by transforming the macroscopic interaction evolution mechanism into the microscopic causal feedback loop.On this basis,the traditional evaluation method of coordination degree was improved.Considering factors such as rail transit operation status,line network distribution,urban development level,and spatial layout,relevant evaluation indicators were selected from the related factors involved in the system boundary.The principal component analysis method was introduced to preprocess the indexes,and the influence of data correlation on the evaluation results was eliminated while the main indexes contributing more than2% of the system were extracted.Then the coupling coordination degree calculation method was used to measure and evaluate the coordination degree between rail transit and urban form.Finally,Changchun city was selected as the case study object,the dynamics equation and parameters of the model were determined according to the actual statistical data,and the system dynamics simulation of rail transit and urban morphology development was carried out.The development trend of their coordination relationship was comprehensively analyzed and evaluated according to the coupling coordination degree calculation method,and optimization suggestions were put forward to improve the comprehensive benefit of the system.The research shows that there is a strong coordination between rail transit and urban morphology system,the stronger the driving effect between the systems.The research is helpful to realize the reasonable operation of rail transit and the continuous optimization of urban form,promote the matching of rail transit construction and urban development level,and point out the key direction for the long-term development planning of rail transit and urban form.