Traffic jams without bottlenecks - experimental evidence for the physical mechanism of the formation of a jam
Traffic jams without bottlenecks - experimental evidence for the physical mechanism of the formation of a jam
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DOI：
10.1088/1367-2630/10/3/033001
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发表时间：
2008-03-04
影响因子：
3.3
通讯作者：
Yukawa, Satoshi
中科院分区：
文献类型：
--
作者：
Sugiyama, Yuki;Fukui, Minoru;Yukawa, Satoshi
高速公路上的交通堵塞是一个非常熟悉的现象。从物理学的观点来看，车辆流系统是相互作用的粒子（车辆）的非平衡系统。多粒子系统的集体效应导致波动增强导致自由流动状态的不稳定，当平均车辆密度超过某一临界值时，会自发地过渡到阻塞状态。因此，瓶颈只是交通堵塞的触发因素，而不是交通堵塞的根本原因。在本文中，我们提出了第一个实验证据，证明交通拥堵的出现是一种集体现象，就像非平衡系统中的“动态”相变和模式形成一样。我们已经在电路上进行了一个实验，以显示在没有瓶颈的情况下出现堵塞。初始条件下，所有车辆以相同的速度均匀分布在环形道路上运动。车辆的平均密度是为不稳定的开始而准备的。即使是微小的波动也会变大，这样就不能维持均匀的运动。最后，堵塞团出现并以与高速公路上堵塞团相同的速度像孤立波一样向后传播。
A traffic jam on a highway is a very familiar phenomenon. From the physical viewpoint, the system of vehicular flow is a non-equilibrium system of interacting particles (vehicles). The collective effect of the many-particle system induces the instability of a free flow state caused by the enhancement of fluctuations, and the transition to a jamming state occurs spontaneously if the average vehicle density exceeds a certain critical value. Thus, a bottleneck is only a trigger and not the essential origin of a traffic jam. In this paper, we present the first experimental evidence that the emergence of a traffic jam is a collective phenomenon like 'dynamical' phase transitions and pattern formation in a non-equilibrium system. We have performed an experiment on a circuit to show the emergence of a jam with no bottleneck. In the initial condition, all the vehicles are moving, homogeneously distributed on the circular road, with the same velocity. The average density of the vehicles is prepared for the onset of the instability. Even a tiny fluctuation grows larger and then the homogeneous movement cannot be maintained. Finally, a jam cluster appears and propagates backward like a solitary wave with the same speed as that of a jam cluster on a highway.