中文摘要：

据上海延安高架路段的交通流录像资料提取的28000余组实测数据，作出流量-密度图，发现在整体低密度时段，流量-密度图可以用Kerner指出的自由流阶段的曲线表示；随着路段整体平均密度的递增，自由流特性越来越不明显。在整体平均密度较低的情况下，存在一定数量的高速度高密度数据。利用观测得到的大量数据，在按密度划分的不同区间内对已有的多个速密关系函数进行最优筛选，得到一种新的分段平衡函数的表达式。最后提出了基于实测数据计算MCLWR模型中各层次车辆所占比例和速度系数的方法。

英文摘要：

It was drawn in this paper that over 28000 ＂car velocity-headway distance＂ data pairs were obtained from the long time video recordings of a section in Yanan Expressway of Shanghai with three traffic circumstances： morning peak hour; morning low traffic hour; afternoon hour. Compared with Kerner＇s flow-density traffic flow model, it was found that as the samples＇ average density increases, the free flow＇s curvilinear flow-density relation that kerner says becomes weaker and nonlinear charater becomes stronger. The real measured data support and enlight the study of traffic flow models. On the aspect of macroscopical differential models, the present paper proposes a method , based on lots of data＇s statistical charater, to compare and study the known equilibrium functions and then to choose the best-fit function in each density section to form a piecewise function, which is much closer to China＇s present traffic conditions. On the aspect of MCLWR models, the present paper gives a method to quantify the proportion of Multi-class Vehicles, which is proposed by Distribution of k-value