Study On The Reasonable Spacing Of Intersections On First Class Highway

In recent years,with the increasing demand for first class highway transportation in our country,the construction of first class highway gradually expanded.First class highway with technical and economic advantages,such as a large traffic capacity and good openness,can effectively promote rapid exchange of traffic flow among the highway and the general trunk road,urban roads and so on.The first class highway is the node and hub of the highway network,which is the key to play the function of exchange of traffic flow for the first class highway.However,there are still some problems about planning of road network and design,such as a large number of highway intersections and the small spacing,so it can not give full play to the transport efficiency of first class highway.This paper draws on the theory and practice results of the first class highway and uses the functional area theory and the capacity theory to study the reasonable spacing of the first class highway.Based on the definition of the interval spacing of the first-class highway,this paper analyzes the influencing factors of the interval spacing of the first class highway,and two reasonable calculation models of the first class highway are established.First class highway plays a important role in the road network,not only to ensure the safety of vehicles driving,but also to improve the traffic flow efficiency,that is,"safety first,taking into account efficiency." In the aspect of safety,the distance calculation model is established by the theory of the functional area and the weaving section theory.The lane-changing theory is used to determine the reasonable spacing.For efficiency,the main road capacity calculation model is established by the analysis of road traffic capacity theory.Finally,the results of the two models are combined to determine the reasonable length of spacing to meet the level of target safety and level of target service.Finally,VISSIM software is used to simulate the route and take the traffic density as the evaluation index to verify the reasonable and feasible.The results of this study have enriched the theoretical knowledge of the design,construction and management of the first class highway,and it has certain practical significance to improve the traffic of the road.