Layout Optimization Of Entrances Of The Beltway

With the rapid growth of Chinese economy,traffic demand of the city are rapidly increasing.The phenomenon of traffic congestion has appeared seriously in many cities because of contradiction between intra-city and inter-city transportation.As Urban outer ring road,the beltway guides the construction and development of city.As the “door” of the beltway,it can guide through traffic flow,connect intra-city and external traffic flow.Rational layout of the entrance of the Beltway can promote travel efficiency of urban traffic,improve road network function,and guide industrial layout beside the beltway to a great extent.Layout optimization of entrances is the key of construction and planning of urban road network and lays the foundation of management of the beltway at later stage.The mode about layout optimization of entrances is studied deeply in this Paper.The contents obtained by this paper are as follows:(1)The function,traffic composition,traffic flow characteristics of the Beltway and deference from highway with the beltway are analyzed.(2)Theories about entrances of the beltway are introduced,including conception,classification,radiation effect of entrances and distance between entrances.The conception and conventional forecasting models of traffic demand of the beltway are analyzed,doing the research is on models about selection of entrance sit of highway and beltway,and comparative analysis is did between highway and beltway.(3)Some influencing factors of entrance layout and key factors considered when Layout optimization model of entrances are analyzed deeply.Theories on GIS and advantages in selection of entrance sit are introduced.A kind of mode about layout optimization of entrances of the beltway based on Voronoi and GIS is put forward.(4)Taking the beltway in Xian for research object,combined with current traffic situation in Xian,traffic demand of the beltway in Xian is forecast and distributed,spatial data is preprocessed with ArcGIS,and methods of layout optimization mentioned already is applied to do layout optimization of entrances of the beltway in Xian based on forecast of traffic demand and relevant spatial data.The result shows that layout optimization scheme fit in with overall planning of Xian(2008-2020),this method applies to layout optimization of Ring Highway in Xian and it provides some theory evidence for approaching urban traffic planning of Xian.