Analysis of crowd vertical evacuation mechanism under different density conditions

In case of emergencies, the efficiency of crowd evacuation in large venues directly impacts whether pedestrians can safely escape. To identify methods for improving evacuation efficiency, this study designed experiments of single-file crowd evacuations on staircases under different speeds and densities. It analyzed pedestrian walking behavior characteristics at various speeds and densities, examined the effects of speed and density on group evacuation, and further investigated the movement mechanisms of groups during vertical evacuation. The experiments revealed that during vertical evacuation, pedestrian walking speed and stride length exhibit a positive linear correlation. The correlation weakens as walking speed increases and strengthens as density increases. One-way ANOVA showed that density has a more significant impact on the differences in walking speed and stride length than speed. At high-density conditions, the "herding behavior" of pedestrians leads to "following behavior," which triggers self-organized queue formation. When the movement trend of the crowd resembles linear motion, an internal self-organized synchronization mechanism is activated, allowing the crowd to perform efficient collective evacuation movements and thus improve evacuation efficiency. These findings deepen the understanding of pedestrian walking behavior characteristics and provide further insights into group movement mechanisms.