降雪条件下城市快速路交通流特性研究

以北京市交通流固定检测器数据为基础,对比分析了正常天气条件和降雪条件下北京市快速路交通流特性的差异,定量描述了降雪对北京市快速路流量和平均运行速度的影响。研究表明,大雪条件下,快速路流量约下降约39%,速度降低10～20km/h,来车时距普遍增加2～4s,饱和流率下降约25%。在此基础上,给出了北京市不同降雪强度下快速路的流量和当量流量水平下平均速度的折减系数。

Traffic Flow Characteristic of City Expressway under Snow Weather

Snow affects the efficiency of the municipal transportation system and has significantly different impacts on different levels of roads in different cities.For understanding the traffic flow characteristics in snow conditions and providing parameters to develop proper traffic management and control strategies,this research uses the fixed detector data as the basis to compare and analyze the differences of traffic flow characteristics under normal weather conditions and snow conditions.It quantitatively describes the snow＇s influence on the traffic flow and the average speed on Beijing expressway.The results show that on expressway,under heavy snow condition,the average traffic flow rate decreases about 39%,the average speed drops about 10-20km/h,the average headway increase 2-4s,and the saturation flow decreases about 25%.Based on the findings,this research establishes the reduction factors for the expressway flow rate under different snow levels and the corresponding average speed.