Phase transition in traffic jam experiment on a circuit
Phase transition in traffic jam experiment on a circuit
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DOI：
10.1088/1367-2630/15/10/103034
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发表时间：
2013-10
影响因子：
3.3
通讯作者：
S. Tadaki;M. Kikuchi;M. Fukui;A. Nakayama;K. Nishinari;A. Shibata;Y. Sugiyama;T. Yosida;S. Yukawa
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文献类型：
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作者：
S. Tadaki;M. Kikuchi;M. Fukui;A. Nakayama;K. Nishinari;A. Shibata;Y. Sugiyama;T. Yosida;S. Yukawa
从物理学的角度来看，交通拥堵的出现是一种动态的相变，当车辆密度超过某一临界值时，交通流变得不稳定，变相为交通拥堵。为了验证这一观点，我们已经进行了一系列的电路实验。在我们之前的工作中(2008 New J.Phys.10 033001)，我们证明了即使在没有瓶颈的情况下，在一定的高密度下也会出现交通堵塞。在这项研究中，我们在名古屋穹顶进行了一个更大的室内电路实验，其中使用高分辨率激光扫描仪观察了汽车的位置。在不同密度下的一系列过程中，我们发现在高密度下发生堵塞流动，而在低密度下自由流动是守恒的。我们还发现了中等密度亚稳的迹象。通过分析速度波动和密度-流量关系，估算了临界密度。这一临界密度的值与实际高速公路上观测到的值是一致的。本实验为将交通拥堵的出现作为一种动态相变的物理解释提供了有力的支持。
The emergence of a traffic jam is considered to be a dynamical phase transition in a physics point of view; traffic flow becomes unstable and changes phase into a traffic jam when the car density exceeds a critical value. In order to verify this view, we have been performing a series of circuit experiments. In our previous work (2008 New J. Phys. 10 033001), we demonstrated that a traffic jam emerges even in the absence of bottlenecks at a certain high density. In this study, we performed a larger indoor circuit experiment in the Nagoya Dome in which the positions of cars were observed using a high-resolution laser scanner. Over a series of sessions at various values of density, we found that jammed flow occurred at high densities, whereas free flow was conserved at low densities. We also found indications of metastability at an intermediate density. The critical density is estimated by analyzing the fluctuations in speed and the density–flow relation. The value of this critical density is consistent with that observed on real expressways. This experiment provides strong support for physical interpretations of the emergence of traffic jams as a dynamical phase transition.