关键词: 交通工程, 信号控制方法, 延误模型, 涡轮式环形交叉口, 环形交叉口

Abstract: The large multilane roundabout normally experiences frequent vehicle lane changes and conflicting traffic flow in different directions at the entrance and exit. This paper proposes a lane level left-turn two-step signal control method combining the unique advantages of the turbo roundabout to control vehicle lane changes. First, through the analysis of the vehicle arrival-departure curves of the first and second stop lines, a signal timing model is established with the minimum average vehicle delay as the target and the signal period, saturation, and green light duration as the constraints. Then, the effect of different control methods, different number of lanes and center island radius on the average vehicle delay is analyzed through modeling. The results show that the lane level left-turn two-step signal control method has a lower delay level compared to the conventional left-turn two-step signal control method, which can reduce the vehicle delay by 6.13 seconds on average. As the number of lanes and traffic volume increase, the proposed method has a lower average delay growth. The larger the radius of the center island, the greater the average vehicle delay, but the increase is marginal. Using the uncontrolled large multilane roundabout at Mengxi Square in Zhenjiang City as an example, VISSIM simulation was performed, and the result shows that the proposed signal control method reduces the average vehicle delay by 8.91% and the stopping rate by 6.85% compared with the traditional left-turn two-step signal control method. This signal control method combining with the turbo roundabout can effectively improve traffic safety and efficiency at large multilane roundabouts.

Key words: traffic engineering, signal control method, delay model, turbo roundabout, roundabout