从车流运动过程分析交通流中流量陡降现象

针对交通流流量密度模型中当密度达到最佳密度Km 附近时流量值出现突然下降的现象，从车流运动过程分析移动车流群在最佳密度附近的流量-时间变化规律和密度-时间变化规律，发现车流群所产生的回波速度是影响流量陡降现象的主要因素。在分析格林希尔治模型缺陷本质的基础上，指出交通流模型采用二阶段模型的必然性，并建立了相应模型。

Analysis on Traffic Flow Breakdown from Vehicular Traffic Movement

Being based on the traffic flow breakdown appeared when the best density near Km being reached in the traf-fic-flow-density model,in this paper,the flow-time change law and the density-time change law around the best density of the moving vehicular traffic flow have been analyzed,which has shown that the velocity echo generated from the mov-ing traffic flow is a major factor for the traffic flow breakdown.Based on the analysis on the nature of the defect of Greenhill model,in this paper,the necessity of using two-stage model for traffic flow model has been pointed out and the corresponding model has been established.