A Study Of Highest-Level Urban Road Network Planning Method

As the highest-level urban road,the urban expressway network guides and restricts the overall development of the city,and its importance is self-evident.The research on urban expressway network planning method started late in China,and the level of planning and construction is still far worse than that of foreign developed countries.The expressway network has low efficiency of traffic service in the urban overall road network,which limits the further development of the city.In view of the above problems,this paper first analyzes the relevant theoretical basis of urban expressway network planning,including its development background,characteristics and functions,and basic planning requirements.It focused on the advantages and disadvantages of the three planning methods: the "traffic location theory",the "location-based traffic line length 1/2 attraction theory” and “control and optimization of urban spatial elements based on 'point,line and surface'”.Secondly,it analyzed and demonstrated the advantages and disadvantages of different expressway network scale prediction methods such as density method,analogy method and supply and demand balance method.By analyzing the non-linearity coefficient,road network quickness index and road network connectivity index and other road network characteristics,the method of urban road network layout based on cobweb model is proposed.Based on the analysis of its bionics principle,the method of fast road network loop spacing and ray number planning is clarified.In addition,based on the theory of fast road section and node design,the advantages and disadvantages of rhombic interchange,ring interchange,cloverleaf and directional interchange and their applicable conditions are compared.The number,spacing and length of the lane of the expressway entrance and exit are clarified.The setting requirements and related regulations,compared with different evaluation methods and finally selected the fuzzy comprehensive evaluation method to construct a rapid road network planning evaluation index system.Finally,combined with the expressway network system planning of Huai'an City,the case analysis is carried out to further verify the scientific rationality of the research planning and evaluation method,which has certain reference value.