A Computation Method of Coordinated Signal Cycle for Four-Limb Roundabout Intersection Based on Conflict Analysis

In view of the insufficient capacity of non-signal four-limb roundabout intersection,eight sets of traffic signal are set up.Their signals are coordinated.In the coordinated signal scheme,straight flow mostly needs to stop one time,and left-turn flow mostly needs to stop two times.The composition of the traffic flows of roundabout intersection is analyzed in detail;the conflicts between traffic flows are thoroughly studied.A method of computing the signal cycle for the coordinated signal control scheme is invented based on the Webster cycle formula.This method is successfully used to traffic signal control of the Center-square roundabout intersection of Zhuzhou City of Hunan Province.