基于微观特性的左弯待转区对交叉口通行能力影响研究

Impact of Left-turn Waiting Area on Capacity of Intersection Based on Microscopic Characteristics

为探寻左弯待转区对交叉口通行能力的影响,划分了左转车道类型及左转车辆排队形态,分析了待转空间增大带来的左转车辆通行能力增量,计算了绿灯间隔时间的增加导致左转车辆通行量的降低值以及排队条件的改善造成直行车辆通行量的增加值,建立了交叉口通行能力综合计算模型。通过具体算例得出在左弯待转区和左转拓宽车道不同长度以及左转车辆不同加速度条件下通行能力增量。结果表明:左转车辆通行能力增量随着待转区长度的增加和左转车辆加速度的增加均呈现增长的趋势,且分别符合线性函数关系和对数函数关系。当左转拓宽车道长度增加时,其对直行车辆通行能力的影响逐步变小。研究成果可为左弯待转区的设置提供一定的理论依据与决策支撑。

To explore the impacts of waiting area for left-turning on capacity of intersection, the types of lanes for left-turning and shapes of queuing vehicles waiting for left turning were divided; the capacity increments of left-turning vehicles due to extended waiting area was analyzed and the reduction of left turning traffic volume resulted from the prolonged green light interval and increased capacity of through vehicles due to improved queuing conditions were calculated. The compre- hensive calculation model for capacity of intersection was developed. The capacity increment of left-turning traffic was cal- culated corresponding to different length of left-turn waiting area and widened lane exclusive for left-turning and different acceleration of left-turning vehicles through an example. The results indicate that the left-turning traffic capacity increases both with the extended length of waiting area and acceleration of left-turning vehicles and the relation between them can be expressed with linear function and logarithmic function respectively. In addition, left-turning traffic waiting zone exerts decreasing impact on capacity of through traffic with the extended length of widened lane exclusive for left-turning traffic. This research results can provide some theoretical basis and support for decision on arrangement of the waiting area for leftturning traffic.