基于实测数据的交通流模型比较研究

A COMPARATIVE STUDY ON TRAFFIC FLOW MODELS BASED ON MEASURED DATA

依据上海延安高架路段的交通流录像资料提取的26000余组实测数据,作出流量-密度图,发现随着路段整体平均密度的递增,Kerner指出的低密度自由流阶段的曲线特性越来越不明显;而在整体平均密度较低的情况下,又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平衡函数进行最优筛选,得到分段平衡函数的表达式,使交通流模型更加贴近真实交通状况.最后提出了基于实测数据计算激进型驾驶者比例的方法,该方法的关键在于利用各种经过特征值变换后的平衡函数形式模拟已有数据的区域边界.

Most of the papers that we can read about traffic flow models focus on interpreting traffic phenomenonsy. It is drawn in this paper that over 26 000＂car velocity-headway distance＂data pairs are obtained from the long time video recordings of a section in Yanan Expressway of Shanghai with three traffic circumstances： peak hour;low traffic hour;snow day.Compared with Kerner＇s flow-density traffic flow model,we can find that as the samples＇ average density increases,the free flow＇s curvilinear flow-density relation becomes weaker and there will be nonlinear charateristic.Some new interesting phenomenons,such as＂high velocity -small headway distance＂data in the traffic flow that has low average density only,are found from the Fig.1～Fig.3 and are discussed in the paper. Real measured data support and enlight the study of traffic flow models.On the aspect of macroscopical differential models,this paper propose a method to choose the best-fit function in each density section to form a piecewise function,which is much closer to present Shanghai traffic conditions.On the aspect of cellular automata models,this paper give a method to quantify the proportion of aggressive drivers,which is proposed by means of fitting different equilibrium functions to real measured data.