When fire occurs in a road tunnel, the rapid spread of smoke results in limited visibility for crowds, making it difficult for them to evacuate quickly. Meanwhile, pedestrians generally evacuate in groups due to their existing social relationships. However, the influence mechanism of group behavior on evacuation dynamics under poor visibilities in tunnels is still unclear. To study the evacuation performance of individuals and social groups, a series of tunnel evacuation experiments were carried out under zero visibility conditions. The results indicate that group behavior could improve evacuation efficiency under bad visibility conditions, because pedestrians in groups can walk more quickly and they are more inclined to choose the nearest exit to escape. Due to the increased sense of safety, the average movement speed of social groups is higher, which is more useful for the evacuees with poor sense of direction. Moreover, different movement patterns are adopted by pedestrians to obtain surrounding information and avoid conflicts under zero visibility conditions. The movement speed in different patterns is also different. Furthermore, the exit choice of pedestrians in the tunnel is influenced by the familiarity with exits and the initial facing direction under no visibility conditions. The study can be helpful for management to develop emergency evacuation plans for crowds in road tunnels.

中文翻译：

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看不见的隧道中个人和社会团体的疏散表现

当公路隧道发生火灾时，烟雾迅速蔓延，导致人群视野有限，难以快速疏散。同时，行人由于已有的社会关系，一般会成群疏散。然而，隧道能见度较差时群体行为对疏散动态的影响机制尚不清楚。为了研究个人和社会群体的疏散表现，在零能见度条件下进行了一系列隧道疏散实验。结果表明，在能见度较差的情况下，群体行为可以提高疏散效率，因为群体中的行人可以走得更快，并且更倾向于选择最近的出口逃生。由于安全感增强，社会群体的平均移动速度更高，这对于方向感较差的疏散人员来说更有用。此外，行人在零能见度条件下采用不同的运动模式来获取周围信息并避免冲突。不同模式下的移动速度也不同。此外，隧道内行人的出口选择还受到对出口的熟悉程度以及无能见度条件下初始朝向的影响。该研究有助于管理层制定公路隧道人群紧急疏散计划。