The Analysis Of Roundabout’s Capacity And The Measures Of Improvement

Roundabouts have played a very important role in the development of the urban traffic.However, with the increasing demand for urban traffic, the traffic efficiency of roundabout isseriously reduced, and the shortcomings is increasingly prominent. Therefore, within thewide range of transforming domestic roundabout into the cross-shaped intersection of signalcontrol, the herd phenomenon roundabouts in the eighties and nineties are facing the fate of"all removed, one does not leave". However, the removal, alteration or retained of theroundabout do not have a clear standard and evaluation system.This article discusses several calculation methods of the cross-shaped intersection ofsignal control at home and abroad, and through case studies, compared the method of capacitycalculation that is more suitable for the traffic situation in China. At the same time, itdiscussed the method of capacity calculation under different control modes using the gapaccepted theoretical mode which is relatively mature.Then this paper compares thecross-shaped intersection of signal control and the roundabouts under different control modesusing the calculation methods which the previously drawn, and come to the capacity of thetwo intersections in a different proportion of turn around or different layout of import Roadlane. And it draws the traffic of the two intersections through the comparing of the twointersections. The traffic of roundabout adapted is more small compared with theCross-shaped intersections, but roundabout has its own unique characteristics in the samecapacity, so should through the comprehensive analysis of the traffic of roundabout andenvironmental impact factors to determine the applicable conditions of the roundabout, theneed for removed, and the necessary transformation program. The same time, this papertransform the roundabout according to the actual instance of the intersection of road trafficconditions and traffic survey data, evaluating the effect after the transformation.