Sound Guidance on Evacuation under Limited Visibility: An Experimental Study

In an emergency, like fire or terroristic attack, visibility reduces due to the power failure or smoke, and the sound guidance could be an effective method to improve the pedestrian evacuation. Thus, in this study, we experimentally investigated the evacuation efficiency under conditions of various sound guidance, with different limited visibility. By the extracted trajectories of pedestrians, we analyzed the temporal-spatial features of the density. The main findings include: (1) With the exit width of 1.2 m and the 20% visibility, the sound guidance improves the evacuation efficiency by 12.6%, and the mean time lapse between two successive evacuees passing through the exit reduces by 22.3%; (2) Under limited visibility conditions the power-law index of the complementary cumulative distribution function (CCDF) for the exit under the sound guidance is always higher than that without sound guidance, implying a more fluent bottleneck flow under sound guidance; (3) The sound guidance has limited effect on the crowd temporal-spatial distribution, while the visibility plays a dominant role.