Study On Large City Built Environment Analysis And Its Impact On Public Transportation Traval Behavior Based On TOD

Under the dual pressures of rapid urbanization and motorization,problems such as disorder spatial expansion,serious traffic congestion,and low environment quality have emerged in large cities in China,and “urban diseases” have become increasingly prominent.In recent years,Transit-Oriented Development(TOD)has been widely recognized,which is to systematically coordinate the land development and public transportation construction,and essentially reflect the synergy between city and transportation.However,in the specific implementation process,TOD would be easily conceptualized and lack systematic technique system support.Therefore,this paper proposed a TODbased analysis method for the built environment of large cities,studied impact of built environment factors on resident's public transportation travel behavior,and conducted an empirical analysis taking typical large cities in China as examples.To begin with,TOD concept and design principles were interpreted referring to TOD-related research results and practical experience.Based on widely-used 6D elements of built environment,an analysis index system of built environment was established,with clear definition and calculation method.The relative spatial element data can be extracted by multiple data sources such as statistical yearbook,Gaode Open Platform and digital maps.With convenient data collecting method,unified index calculation method,the analysis index system can be used for the analysis and comparison of built environment on different geographic scales like the whole city,certain areas,blocks or areas around transit stations.Secondly,32 representative domestic large cities were selected according to the population size,economic development and public transit development level,and 20 basic social-economic attribute indices and 36 built environment analysis indices of each large city were calculated separately.The former indices include city area,Gross Domestic Product per capita,daily tourist number,traffic congestion index and public transportation passenger volume,and the latter indices cover built environment 6D elements of density,diversity,design,destination accessibility,distance to transit and demand management.Statistical analysis and spatial analysis were performed for each indicator.Analysis results show that the current land use development intensity and public transportation system scale in large cities are basically matched with the urban population size.High-intensity mixed land development zones,high-level bus and rail transit services,and high parking density areas are concentrated in the central district,showing an urban space pattern of “single center + low density spread”.Moreover,the overall road network density of the built-up area is relatively low.Furthermore,take the above 32 large cities as samples to make multiple linear regression analysis,in which resident's total travel frequency of public transportation was taken as the dependent variable and the other social economic attribute indices and built environment analysis indices were taken as independent variables.The final regression model shows that public transportation system scale,medical service POI density,rationality of public transportation network layout,accessibility to company POI,and parking lot density are the main factors affecting resident's total travel frequency of public transportation.Besides,based on these main factors,use k-means clustering algorithm to divide large cities into four categories.The large cities in different clusters have distinct rail transit network scale.Mature rail transit network would encourage more residents to travel by public transportation,which would transfer part of the bus passenger flow to rail transit flow at the meantime.It is also found that if large cities have higher urban parking lot density,residents would more likely to choose driving as their travel mode.Finally,Nanjing main districts and Singapore,which have similar urban population size and city area were chosen for a case study.The difference between both cities' 6D elements of built environment were quantitatively and visually compared.The result shows that Singapore has formed a multi-center and open-plan urban pattern based on TOD,with residents traveling mainly on public transportation.However,the main districts of Nanjing are still in the stage of single-center mode,whose development intensity and diversity of land use around the subway station,the accessibility to public transportation around housing,and the road density are relatively low.