Traffic Flow Characteristics of Urban Expressway in the Period of Ice and Snow of Cold Areas

Urban expressway is a rapid arterial that connects main areas of the city, and meets the great-amount, long-distance, and high-speed demand of urban traffic. The friction coefficient of roads covered with snow and ice is reduced, and the traffic operation risk is increased in regions with high latitudes, whose winter is long and cold, and those conditions led to the reduction of road capacity and the increase of traffic delays. Using the video detection device, one of the traffic flow information collecting devices, a large number of data in the period of ice and snow of cold area are collected, which is the research base of this paper. The macro and micro traffic flow characteristic of urban expressway under conditions of the snow and ice environment are analyzed, such as the instant traffic flow, the distribution of headway time, and the properties of the speed distribution. The relation models of speed-volume are built. At the same time, the traffic flow characteristic of the urban expressway in the period of ice and snow of cold areas are compared with that of non-snow periods. The outcomes studied above are the foundation for analyzing traffic operation and capacity of urban expressway in the period of ice and snow.