Abstract: The volume，density and speed of space area were defined over again based on the conception of equivalent capacity and the formulas were put forward．Making use of collected traffic flow inform ation of urban expressway，the trafic flow characteristics of urban expressway in Shan ghai were analyzed based on the essential trafic flow parameters of space area，after defining the time interval and choosing appropriate expressway sections．Then the operation situation of expressway was obtained and base models based on three basic traffic flow parameters were set up．

Key words: urban expressway, trafic flow, equivalent capacity, traffic flow base model

摘要： 基于等效通行能力的概念，文章重新定义了空间区域的流量、密度、速度的概念，并给出计算公式．利用已采集 的快速道路交通流信息，合理确定时间段和快速路段，并运用空间区域交通流基本参数分析了快速道路交通流特 性，并得出各快速道路路段的交通运行状态，和交通流3参数基本模型。

关键词: 城市快速路, 交通流, 等效通行能力, 交通流基本模型