Review on Traffic Flow Phenomena and Theory

Aiming at solving severe traffic congestion problem in metropolitan, in the last several decades, a number of traffic flow phenomena were discovered on freeways all over the world. Recent researches on traffic flow focused on developing traffic modes and methodology which could explain and reproduce all these phenomena. In this paper, observed traffic phenomena such as traffic breakdown, hysteresis, stop-and-go traffic and synchronized flow are introduced. Then traffic flow models are classified by their equations of speed, acceleration and second-order acceleration in macroscopic/microscopic or continuous/discontinuous forms. Features of these traffic models and their explanation on traffic phenomena are also discussed.

摘要信号交叉口是城市交通系统的重要组成部分，制定合理的交叉口拥堵和安全治理方案尤为重要。交叉口扩容是缓解交叉口拥堵最直接有效的措施,但是传统的扩容方案（如增加车道，禁止左转和立体交叉等），可能并不能达到预期的效果。由于上游的扩容，下游交叉口的交通状况可能会急剧恶化，导致更长的车辆排队，这些排队车辆可能蔓延至上游交叉口，引起堵塞。此情形在车流量大、交叉口之间距离小和信号灯周期长的情况下表现尤为显著。本文提出了一个简单，准确且实用的方法，用于判定这种下游排队蔓延现象的发生及其种类（循环性或持续性），并且评估这种排队蔓延对上游信号交叉口通行能力的影响。此方法基于最新的美国交通运输署的高速公路通行能力手册。本文还介绍了该方法相应的计算程序表的开发和运用，并给出运用实例。