一种新式的交叉口左转待行区信号控制方法

针对信号交叉口许可相位运行期间直行车与左转车交通冲突严重、通行效率低下的问题，提出一种针对许可相位的新式左转待转区设计方法，设计该组织模式下的信号相位方案并分析了设置左转待转区前后的交通冲突情况。建立新式左转待转区设置后的延误模型，以车均延误最小为优化目标，建立改进后交叉口信号控制参数优化模型，并给出求解算法。以哈尔滨市融江路-群力第六大道交叉口为例，VISSIM仿真表明：尽管提出的方法对次要道路中左转车的延误和停车率不利，但总的车均延误在下降，特别是主路相位延误下降更明显，说明所提方法可行、有效。进一步分析交通流量规模、左转车比例和左转待转区容量等因素对设置左转待转区前后次要道路车均延误的影响，结果表明：当每方向左转待转区容量固定不变时，红灯期间到达的左转车辆数越多，所提方法适用的次要道路交通流量临界点越高，且随着次要道路交通流量的增加，所提方法适用的临界左转比例在下降；在相同交通条件下，每个方向左转待转区容量越大，车均延误就越小，说明每个方向左转待转区容量越大，所提方法的效果越明显。该方法有助于改善含许可相位的信号交叉口交通安全和通行效率。

Signal-control Method for a New Left-turn Waiting Area at Intersections

In view of the low efficiency of traffic flow and serious traffic conflicts between through and left-turn vehicles during the permitted-phase operation at signalized intersections, a new method for setting the left-turn waiting area in the permitted phase was proposed. The corresponding signal phase scheme was designed, and traffic conflicts before and after setting the left-turn waiting area were analyzed. In this study, a delay model was established after setting a new left-turn waiting area, the optimized model of the signal control parameters of the improved intersection was established with the minimum average delay of vehicles as the optimization objective, and the solution algorithm was developed. Taking the intersection of Rongjiang Road and the sixth Qunli Avenue in Harbin, China, as an example, the VISSIM simulation shows that, although the method proposed in this study is not suitable to reduce the delay and the stop rate of left-turning vehicles on the side road, the total delay of vehicles on the side road is reduced and the delay on the main road especially decreases. This highlights that the method proposed hereby is feasible and effective. Furthermore, the influence of traffic volume and the proportion of left-turn vehicles before and after setting the left-turn waiting area, as well as the effect of the left-turn waiting area on the delay on the side road were analyzed. The results show that when the capacity of the left-turn waiting area in each direction is fixed, more left-turn vehicles arrive in red time, the higher the critical point of hourly traffic volume on the side road associated with the method proposed in this study, and with the increase in the hourly traffic volume on the side road, the critical left-turn ratio of the proposed method decreases. In the same traffic conditions, the greater the capacity of the left-turn waiting area in each direction is, the smaller the delay of vehicles, that is, the more effective the method proposed herein is. Therefore, the proposed method improves the traffic safety and efficiency at signalized intersections, including in the permitted phase.