Research And Application Of Time And Space Accessibility Model Of Urban Public Transportation Network

As China’s urbanization process continues to advance,urban residents are increasingly demanding convenience in transportation.Urban social and economic development is severely constrained by the deterioration of traffic conditions.The public transport-oriented urban transport development model is currently recognized as the direction of urban planning development.At present,the planning and design of comprehensive urban public transportation systems in China lack comprehensive theoretical systems and methods.Taking multi-system and multi-level urban public transport network as the research object,and adopting vector grid integrated calculation method,a comprehensive public transport network accessibility model considering the time factors of transportation lines,transfer factors and the service range of transportation stations is established.The model quantitatively analyzes the influence of public transportation lines on the passing area.The main research contents include:(1)Summarize the research status of traffic accessibility at home and abroad,and analyze the factors restricting public transport accessibility.Explain the connotation of transportation accessibility in public transportation planning: mainly manifested in the coordination of different transportation modes and the convenience of transfer in public transportation planning,and the service area of public transportation stations.(2)Study the construction methods of transportation networks and the division of urban comprehensive public transportation systems,and elaborate the usage scenarios and construction rules of different transportation network construction methods.With reference to the example of the composition and division of the integrated public transportation system of typical cities in developed countries,the urban integrated public transportation system is divided into two parts: the line network layer covering all traffic standards and the connection layer consisting of slow-moving passages connecting the station and the surrounding area..(3)By constructing an optimal path search method,a line network layer accessibility model that comprehensively considers time factors and transfer factors is established,and the line network layer accessibility under the joint action of time factors and transfer factors is obtained.Using the cost grid calculation method,considering the service range of the traffic station,the accessibility of the connection layer is obtained.Using the improved vector grid algorithm,the line network layer accessibility and the connection layer accessibility are combined to obtain the results of the comprehensive public transport system accessibility.(4)Take the current situation of urban public transportation in the main urban area of Chengdu as an example.Respectively calculate line network layer accessibility,connection layer accessibility and regional integrated public transport system accessibility.The calculation results show that the accessibility of the integrated public transportation system can reflect the difference in speed of different transportation lines,the interactive characteristics of the transportation lines,and the connection between the transportation network and the surrounding area,reflecting the advantages of the comprehensive public transportation system accessibility model.(5)Analyze the impact of different line types on accessibility in the regional integrated public transportation system.The results show that the urban rail transit loop has a strong effect on improving the accessibility of the area.The radial line of the rail transit effectively improves the accessibility away from the central area,and the bus radiation lines away from the main urban area have a limited effect on accessibility.According to the effect of line type on overall reachability,from the perspective of improving reachability,suggestions for future line network planning are given.The constructed calculation model of the urban comprehensive public transport system accessibility provides model support for the line network planning principle of “station-oriented,area-based,layer-by-layer network,and overall optimization”.The research results help to improve the evaluation and planning level of the city’s comprehensive public transportation system.