基于激波分析理论的交通拥堵传播和消散机理研究

交通拥堵传播和消散机制的研究是解决城市拥堵问题的核心基础工作。三角形基本图是一种广泛使用的宏观交通流模型,在该模型中有两种特征线,前置波和后置波。前置波表示畅通交通流的动态演化进程,后置波表示拥堵交通流的动态演化进程。当畅通交通流与拥堵交通流交叉时会形成一条激波带,激波带分离了两种交通状态,且以一定的速度向上游和下游传播。拥堵的传播和消散本质上是激波的传播。最后,以一数字算例,分析了由下游瓶颈造成的拥堵向后传播的规律以及瓶颈能力恢复后拥堵消散的规律。

A Shock Wave Theory Based Analysis of Propagation and Dissipation Mechanism of Traffic Congestion

Studies on the propagation and dissipation mechanism of traffic congestion are the core and foundation of efforts in dealing with urban traffic congestion.Triangular fundamental diagram is a widely used model to describe the macroscopic traffic flow.The model is composed of two characteristics curves: a forward wave and a backward wave.The forward wave indicates the dynamic process of the evolution of unobstructed traffic flow whereas the backward wave indicates the dynamic process of the evolution of congested traffic flow.When the unobstructed and the congested traffic flows cross over,a shock wave belt will be generated which separates the two traffic statuses and propagates simultaneously upstream and downstream at certain speed.Therefore,the propagation and dissipation of congestion is in nature the propagation of the shock wave.Finally,in a numerical example,the paper analyzes the patterns for the backward propagation of the congestion after the formation of the downstream bottleneck and the dissipation of the congestion once the bottleneck is unclogged.