Department of Advanced Interdisciplinary Studies, Graduate School of Engineering, The University of Tokyo, Meguro-ku, Tokyo, Japan.
Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan.
PLoS One. 2018 Dec 19;13(12):e0208496. doi: 10.1371/journal.pone.0208496. eCollection 2018.
In this work, we investigate properties of bidirectional pedestrian streams by studying different experimental datasets from multiple authors. Through the comparison of a scenario where lanes naturally form with two others where lane formation is either obstructed or facilitated, we show the relationship of different pedestrian quantities in regard to the flow ratio (or directional split). On this scope, two measures to account for the degree of congestion and self-organization are introduced. The analysis of the results reveals that the balanced case (where flow is almost equal in both directions) has very peculiar properties which depends on the existence or not of organized lanes and their stability. While the balanced case generally shows the highest level of congestion, this property can quickly change after lanes are formed and when they remain stable. An in-depth investigation revealed that capacity in bidirectional streams is characterized by a dual nature: conflicts with the counter flow and self-organization in lanes. Both aspects have been described using a mathematical model which allowed to define a function for capacity in relation with flow ratio and environmental/cognitive aspects. The expression for capacity proposed in our work agrees with several studies from the literature, eventually allowing to understand the differences among them. We believe our function for capacity enables a more universal treatment of bidirectional streams compared to previous definitions, since it allows to account for steady and non-steady state conditions which represent important mechanisms in their dynamics. The framework introduced here may also help measuring the influence of environmental/cognitive changes in relation with the capacity of bidirectional pedestrian streams.
在这项工作中，我们通过研究来自多位作者的不同实验数据集来研究双向行人流的特性。通过比较自然形成车道的场景与车道形成受阻或受促进的另外两个场景，我们展示了不同行人数量与流量比（或方向分割）之间的关系。在这个范围内，引入了两种措施来衡量拥堵程度和自组织程度。对结果的分析表明，平衡情况（两个方向的流量几乎相等）具有非常特殊的性质，这取决于有组织的车道的存在及其稳定性。虽然平衡情况通常显示出最高的拥堵水平，但在形成车道后，当它们保持稳定时，这种特性可能会迅速改变。深入的调查揭示了双向流中的容量具有双重性质：与反向流的冲突和车道中的自组织。这两个方面都使用数学模型进行了描述，该模型允许定义一个与流量比和环境/认知方面有关的容量函数。我们工作中提出的容量表达式与文献中的几项研究一致，最终能够理解它们之间的差异。我们认为，与之前的定义相比，我们提出的容量函数可以更普遍地处理双向流，因为它允许考虑稳态和非稳态条件，这些条件是它们动力学中的重要机制。这里介绍的框架还可以帮助衡量与双向行人流容量有关的环境/认知变化的影响。
