Abstract Based on an empirical study of floating car data (probe vehicle data), we have found the following microscopic features of empirical synchronized flow that are relevant for jam warning methods: (i) In accordance with Kerner’s three-phase traffic theory, the empirical speed decrease (speed drop) denoted by Δv that occurs due to vehicle deceleration at the upstream front of synchronized flow is a complex time function. (ii) The empirical function Δv can be considered a “jam wall” at which different vehicles exhibit sometimes very different speed drops Δv occurring at different road locations. Because each of the vehicles decelerates within the “jam wall” at different road locations, the “jam wall” moves in space and in time. (iii) The spatiotemporal structure of the empirical “jam wall” is determined by alternations of the synchronized flow and wide moving jam traffic phases at the upstream front of a congested traffic pattern. (iv) During some time intervals, the “jam wall” can disappear and then it can appear once more, and so on; during “jam wall” disappearance, one or a few vehicles can pass a bottleneck while moving in free flow. These empirical findings can be important for the development of reliable jam warning methods as well as other ITS-applications.

中文翻译：

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基于相位的拥塞警告：基于浮动车数据的同步流分析

摘要 基于对浮动车数据（探测车数据）的实证研究，我们发现了与拥塞预警方法相关的经验同步流的以下微观特征：（i）根据 Kerner 的三相交通理论，经验同步流由 Δv 表示的速度下降（速度下降）由于车辆在同步流上游前端减速而发生，是一个复杂的时间函数。(ii) 经验函数 Δv 可以被认为是一个“堵墙”，不同的车辆有时会在不同的道路位置表现出非常不同的速度下降 Δv。由于每辆车在不同道路位置的“堵墙”内减速，“堵墙”在空间和时间上移动。(iii) 经验“拥堵墙”的时空结构是由拥堵交通模式上游前沿的同步流和宽移动拥堵交通阶段的交替决定的。(iv) 在某些时间间隔内，“堵墙”可能会消失，然后又会再次出现，以此类推；在“堵墙”消失时，一辆车或几辆车可以自由流动地通过瓶颈。这些经验发现对于开发可靠的拥塞警告方法以及其他 ITS 应用非常重要。