Signal control and simulation of a typical roundabout

Signal control plays an importing role on resolving traffic jam on big roundabout. This paper analyzes signal control methods and characteristics on roundabout home and abroad. The characteristics of signal control and non-signal control on the roundabout were analyzed by comparison. Further more, it was introduced to discuss signal control methods on roundabout, emphasize the principle, steps and designing parameters of turning-left two-step signal control method (TTSM) and so on. Finally, it was illuminated through a typical roundabout operation control of Harbin Hongbo intersection. From analysis on delays and level of services (LOS) with Vissim software before and after, it showed that TTSM was an effective method to roundabout control, especially for the roundabout with saturated flow of turning left. It efficiently dealt with traffic jam on roundabout.