大雨天气下高速公路交通流特性分析

Analysis of Traffic Flow Characteristics of Expressway Under Heavy Rain Weather

为研究大雨对交通流特性的影响,以旧金山奥克兰境内的I880N高速公路98#大街南侧路段为研究对象,在分析交通流速度随时间变化的基础上,研究不同车道位置在大雨天气下交通流速度的变化情况;分析大雨时速度-流量散点图的分布规律;采用实际数据标定Van-Aerde、Greenshields两种经典的宏观交通流模型。结果表明:与无雨相比,大雨时自由流速度、通行能力分别下降约11.2%和19.6%,阻塞密度升高约50%;大雨时车辆速度呈弥散分布,交通流趋于不稳定状态,大雨更容易引起交通拥堵,且与内侧车道相比,外侧车道的交通流速度分布较为离散。

To study the effect of heavy rain on traffic flow characteristics, the south section of No. 98 Avenue of I880N expressway in Oakland of San Francisco is taken as a research object, the change of the speed under heavy rain in different lanes is studied based on the analysis of the time variation of heavy rain and traffic flow rate. The distribution law of velocity-flow dispersion point is analyzed under the heavy rain intensity. Two typical macroscopic traffic flow models are calibrated by the use of the actual data. The results show that when compared with the condition without rain, during heavy rain the free flow speed and the capacity respectively decrease by about 11.2% and 19. 6 % , and the blocking density increases by about 5 0 % . The speed of the heavy rain is dispersed, and the traffic flow tends to be unstable. Besides, the heavy rain is more likely to cause traffic congestion, and the lateral traffic flow velocity distribution is more discrete compared with the inside lane.