基于交叉口交通流影响程度的不利天气分级方法

信号交叉口的交通流由于受到不利天气的影响呈现不同特征，根据不同级别不利天气设置有针对性的信号控制方案，是减少天气对交通运行影响的重要途径.本文选取北京市不同规模、不同类型的信号交叉口为观测对象，以视频采集方式获取了2012 年 4 月–2013 年2 月期间不同类型和强度的不利天气条件下交叉口交通流数据，通过显著性差异分析、回归拟合的方法，分析了交叉口直行车道饱和车头时距、饱和流率及起动损失时间等特征参数的变化，构建了信号交叉口特征参数的影响模型，量化了降雨、降雪天气对交叉口交通流的影响.最后，基于不利天气对交通流特征参数的折减程度，将不同类别的不利天气统一划分为四级，并明确了各级不利天气对应的饱和流率折减范围，为制定天气响应型的交通控制方案提供了重要的参数基础.

Study on Adverse Weather Classification Considering the Traffic Flow Influence Degree at Intersections

The traffic flow at signal intersection shows different characteristics due to the influence of adverse weather. Setting specific signal control scheme in adverse weather conditions is an important way to reduce its negative influence on the traffic. The signal intersections of different types and scales in Beijing are selected as the investigation spots in this study. Based on the weather data and traffic flow data obtained from video detectors through the months of April 2012 and February 2013, the characteristics of indicators including saturation headway, saturation flow rate and start- up lost time in different intensities of adverse weather are analyzed. The relationship models between the indicators and the precipitation are established by significance testing and regression modeling. Consequently, the influence of the rain and snow on the traffic flow of intersections is described quantitatively. Finally, the adverse weather is classified into four grades based on its influence degree on the intersection traffic. These traffic flow characteristics in every grade of adverse weather provide applicable parameters for the optimization of traffic control scheme.