Research On Influence Mechanism Of Urban Transport Infrastructure On Urban Agglomeration And Expansion

City is a very complex,multi-functional system,and urban transport infrastructure has an important impact on the shape of urban Expansion.It is evidence that highway infrastructure can promote the formation of low-density and urban expansion in Atlanta of the U.S.and urban rail transit can guide the multi-center patterns of urban expansion in Tokyo of Japan.We find the economics problem from the phenomena above,that is why urban transportation infrastructure has an impact on urban expansion.Using the theory of agglomeration economics,public goods and threshold, this paper attempts to study the mechanism how urban transport infrastructure affects urban expansion,as well as whether there is different patterns of urban expansion guided by different transport infrastructure,aiming at providing some effective supply policy of urban transport infrastructure in order to enhance the efficiency of cities.Scholars at home and abroad study the issue from the aspects of land,planning, and transport demand management,but their research considers urban transport as a whole.However,urban transport have different levels and functions,they also have different shapes of network as an infrastructure layer.Therefore,with the assumption of other conditions remaining unchanged,the paper analyzes the influence mechanism of urban transport infrastructure on urban agglomeration and expansion from the perspective of agglomeration economics and transport location,which is benefit for guiding transport policy.Paper made the following innovative research:Firstly,the innovation of research perspective.The paper puts the variable of matching of transport nodes,accessibility of line and differences of network into research,which are always neglected.Secondly, the innovation of economic attributes of urban transport infrastructure.The paper brings forward that urban transport infrastructure has the attributes of shared, congestion,accessibility,network and threshold,and the attributes of shared and threshold are put forward from a new perspective.The third is the innovation of influence mechanism of urban transport infrastructure on urban agglomeration and expansion.The paper builds up an analytical framework,and describes the meaning of variables of transport cost from three levels of node,line and network.The fourth innovation is about supply policy of urban transport infrastructure.The paper applies the attributes of threshold into the analysis of how urban transport infrastructure affects urban agglomeration and expansion,and brings forward that we should adopt continuous policy in order to maintain sustained growth of urban agglomeration effect.The main conclusions in the paper are as follows:Firstly,this paper brings forward that urban transport infrastructure is a kind of shared and productive public resources within the city,which can reduce living costs of residents and production costs of enterprise.The second,the paper thinks that urban transport infrastructure directly affects the consumption function and production function,which brings city economies of agglomeration.At the same time,urban expansion resulting from increased transport costs and traffic congestion also brings non-economies of agglomeration,and restrain urban agglomeration.Thirdly,the paper builds up a model to analyze the relationships between transport costs and city size.It finds that city expands along with decrease of transport costs,and urban agglomeration economies can be realized by improving urban transportation infrastructure.Fourthly,the paper proposed that matching of transport nodes,accessibility of line and differences of network are the important factors affecting transport costs.Fifthly,it is brought forward that continuous supply policy can promote maintain sustained growth of urban agglomeration effect.The six,the paper points out that the reason that the reason why the city expands along transportation infrastructure is that development of the city is always running down the direction of cost-saving.The seven,the suggestion of developing Beijing's transportation is given.The author proposes that radiation patterns of urban rail transport network should be developed,the urban transport hub for the convergence should be strengthened,and public transport infrastructure should be put in the first.