A Study Of Interchange Spacing

In the planning of the highway, Apart from the road corridor zone, the interchange settings is another important planning elements, and one of the key factors is the reasonable interchange spacing. This includes the average interchange spacing, minimum and maximum spacing. Particularly, - interchange minimum spacing direct impact on the highway level of service, operational efficiency , the stability of traffic and the security of traffic. After more than 20 years of China's expressway construction, more and more examples of the works is less than the minimum interchange spacing requirements of the existing norms, Designers and builders who were asked to relax the minimum spacing of Interchange restrictions and maximum distance calls is also growing . Research results of the reasonable smallest distance between Interchanges is very important to China's highway planning and construction.The current interchange spacing study on the highway is not adequate, Only in a small number of papers have appeared, Most of the contents is the summary of interchange design and the Introduce of some form of interchange, and the Ramp and horizontal alignment design studies. Interchange standard spacing studies, Nationwide collected a total of 117 samples, use statistical analysis and foreign data , lastly, summarize the results of standard spacing. The smallest Interchange spacing is the focus of this paper,From Interchange Construction length, traffic signs and direct traffic impact can analysis the smallest interchange spacing with Independent lanes. The minimum interchange with Auxiliary lanes depends on the length of the intertwined lane, In this paper, through the traffic flow theory, through different lanes and different import and export, by the general assumption of the traffic flow parameters, Analyse different intertwined length on Interchange service levels and the impact of operational speed, conclude the minimum intertwined length,then conclude the minimum spacing.Through statistical analysis and theory with the technical lines, In general area, Interchange standard distance is 15 to 25 km; In big cities and around major industrial areas, Interchange standard distance is 5 to 10km. Independent interchange minimum distance is 2.0 km, the minimum distance Of Interchange With Connect auxiliary lane is 1.2 km. In big cities or major industrial areas Interchange greatest distance should not be more than 20 km around, In general Area it is not appropriate more than 3 0 km around, In sparsely populated or economically less developed areas, Interchange greatest distance can be the largest increase, but not more than 4 0 km.In this paper, research results is more in line with china interchange spacing distribution, As a result of the planning and construction of highways have some guidance value.