中文摘要：

本文以京港澳高速公路湖北省内金山—武汉南路段内的交通流检测器及其附近设置于路侧的公路气象站的历史数据为主要研究数据，针对雾天低能见度等天气因素，分析有无雾及不同能见度条件对车辆速度均值及速度离散型的影响；研究在雾天条件下，不同车道位置、不同车辆类型、不同时间时段的车辆行驶速度的差异性；基于交通流Greenshield经典V-K关系，采用非线性回归方法，建立雾天车辆平均行驶速度综合预测模型，模型的拟合优度达到80%。研究成果对研究公路沿线能见度因素对行车安全影响，分析雾天等低能见度条件下的公路通行能力，制定雾天等低能见度条件下可变速度控制等交通控制措施具有重要参考与借鉴意义。

英文摘要：

This paper explores the effects of traffic visibility on characteristics of vehicle speed, based on the traffic and road weather data of detectors positioned on the road segment between Jinshan and Wuhannan interchange of Jinggangao （G4） expressway in Hubei province. Focusing on the limited visibility weather element, this paper analyzes the effects of visibility on the mean speed and speed variation by fog or non-fog weather, or under fog weather condition with different visibility; speed characteristics are deeply explored from aspects of different factors of traffic lane, vehicle types and temporal hour, utilizing detailed traffic data containing traffic lane and vehicle type information. The comprehensive speed prediction model is built under fog weather condition considering several factors based on the classic traffic flow theory of Greenshield’s V-K relation, and the goodness-of-fit of the speed prediction model reaches 80%approximately. The research results of this paper can be useful or as a reference to impacts analysis of limited visibility on traffic safety, operation, and traffic capacity analysis, or decision making process of traffic control measures such as variable speed limit under adverse road weather conditions.