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Power laws and phase transitions in heterogenous car following with reaction times
Physical Review E ( IF 2.4 ) Pub Date : 2021-03-01 , DOI: 10.1103/physreve.103.032202
A. Sai Venkata Ramana , Saif Eddin Jabari

We study the effect of reaction times on the kinetics of relaxation to stationary states and on congestion transitions in heterogeneous traffic using simulations of Newell's model on a ring. Heterogeneity is modeled as quenched disorders in the parameters of Newell's model and in the reaction time of the drivers. We observed that at low densities, the relaxation to stationary state from a homogeneous initial state is governed by the same power laws as derived by E. Ben-Naim et al., Kinetics of clustering in traffic flow, Phys. Rev. E 50, 822 (1994). The stationary state, at low densities, is a single giant platoon of vehicles with the slowest vehicle being the leader of the platoon. We observed formation of spontaneous jams inside the giant platoon which move upstream as stop-go waves and dissipate at its tail. The transition happens when the head of the giant platoon starts interacting with its tail, stable stop-go waves form, which circulate in the ring without dissipating. We observed that the system behaves differently when the transition point is approached from above than it does when approached from below. When the transition density is approached from below, the gap distribution behind the leader has a double peak and is fat-tailed but has a bounded support and thus the maximum gap in the system and the variance of the gap distribution tend to size-independent values. When the transition density is approached from above, the gap distribution becomes a power law and, consequently, the maximum gap in the system and the variance in the gaps diverge as a power law, thereby creating a discontinuity at the transition. Thus, we observe a phase transition of unusual kind in which both a discontinuity and a power law are observed at the transition density. These unusual features vanish in the absence of reaction time, i.e., when the vehicles react instantaneously to a perturbation ahead (e.g., automated driving). Overall, we conclude that the nonzero reaction times of drivers in heterogeneous traffic significantly change the behavior of the free flow to congestion transition while it doesn't alter the kinetics of relaxation to stationary state.

中文翻译:

随时间变化,异质车中的功率定律和相变

我们使用纽厄尔模型在环上的仿真研究了反应时间对弛豫动力学到稳态的动力学的影响以及对异构流量中的拥塞转变的影响。在Newell模型的参数和驱动程序的反应时间中,异质性被建模为淬灭性疾病。我们观察到,在低密度下,从均匀的初始状态到稳态的弛豫受E.Ben-Naim等人推导的相同幂定律支配,交通流中的聚类动力学,物理。修订版E 50,822(1994)。处于低密度的静止状态是一个大型车辆排,最慢的车辆排在该排的首位。我们观察到在巨大排内形成的自发果酱,它们以停滞波浪的形式向上游移动,并在其尾部消散。过渡发生在巨型排的头部开始与其尾部相互作用时,形成稳定的停走波,这些波在环中循环而不会耗散。我们观察到,当从上方接近过渡点时,系统与从下方接近时,系统的行为有所不同。当从下方接近过渡密度时,前导区后面的间隙分布具有一个双峰,并且是肥尾的,但具有有限的支持,因此系统中的最大间隙和间隙分布的方差往往与尺寸无关。 。当从上方接近跃迁密度时,间隙分布成为幂定律,因此,系统中的最大间隙和间隙中的方差会随着幂律而发散,从而在跃迁处产生不连续性。因此,我们观察到一种不寻常的相变,其中在跃迁密度处都观察到了不连续性和幂律。这些不寻常的特征在没有反应时间的情况下即消失,即当车辆对前面的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。间隙分布成为幂定律,因此,系统中的最大间隙和间隙的方差会随着幂定律而发散,从而在过渡时产生不连续性。因此,我们观察到一种不寻常的相变,其中在跃迁密度处都观察到了不连续性和幂律。这些不寻常的特征在没有反应时间的情况下即消失,即当车辆对前面的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。间隙分布成为幂定律,因此,系统中的最大间隙和间隙的方差会随着幂定律而发散,从而在过渡时产生不连续性。因此,我们观察到一种不寻常的相变,其中在跃迁密度处都观察到了不连续性和幂律。这些不寻常的特征在没有反应时间的情况下即消失,即当车辆对前面的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。从而在过渡处产生不连续性。因此,我们观察到一种不寻常的相变,其中在跃迁密度处都观察到了不连续性和幂律。这些不寻常的特征在没有反应时间的情况下即消失,即当车辆对前面的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。从而在过渡处产生不连续性。因此,我们观察到一种不寻常的相变,其中在跃迁密度处都观察到了不连续性和幂律。这些不寻常的特征在没有反应时间的情况下即消失,即当车辆对前面的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。当车辆对前方的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。当车辆对前方的扰动立即做出反应时(例如,自动驾驶)。总的来说,我们得出的结论是,异构流量中驱动程序的非零反应时间会极大地改变自由流向拥挤过渡的行为,而不会改变松弛到平稳状态的动力学。
更新日期:2021-03-01
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