Study On The Setting Condition Of Composite Interchange

The process of speeding up the city urbanization and the development of regional traffic, city ring highway, district ring highway and the district first-class or second-class highway constantly access to the national highway network, produced a large number of new interchanges. When the net distance between a new interchange and an existed interchange does not meet the requirement of vehicle operation, influencing traffic capacity and traffic safety. If two interchanges set as composite interchange, that impact will improve. Based on the composite interchange as the research object, study its setting condition.First of all, according to the connection mode of the composite interchange were classified: auxiliary lane connection, collector-distributor road connection, as well as the ramp connection, combining with the actual project, analysis of the advantages and disadvantages of three connections. Secondly, the setting condition of the composite interchange was studied. By analyzing the influence factors of the setting condition on the composite interchange, combining with the norms of our country and the United States, the composite interchange was defined. The traffic flow capacity model and the minimum net distance model of interchange were established, and the setting condition of the composite interchange based on traffic conversion and geometric constraint were put forward. Again, setting condition of the composite interchange which connected with weaving lane, based on the influence factors of weaving area and weaving lane length of composite interchange, weaving area length of composite interchange calculation model was established, and setting condition of composite interchange which connected with auxiliary lane or collector-distributor road was put forward. In the end, the setting condition of composite interchange which connected with ramp was studied. By analyzing the geometric characteristics and traffic flow characteristics of the connect ramp, and comparing with the stereo separation between ramps, the setting condition of the composite interchange which connected with ramp was put forward.On one hand, the research is to study interchange under the condition of existed road with a big network density, providing the ideas, methods, to ensure the traffic capacity and traffic safety of interchange; On the other hand, the research is to study compsite interchange, to quantify three connections. Research results have theoretical guidance and engineering significance to the application of composite interchange.