Research on pedestrian evacuation considering group behavior under zero-visibility condition

The influences of group behavior on pedestrian evacuation under zero-visibility conditions are analyzed in depth by combining controlled experiments with modeling and simulation in this work. Initially, by experiments on pedestrian evacuation under zero-visibility conditions, typical evacuation behaviors are identified such as group behavior, auditory guidance behavior, and wall-following behavior. The pedestrians rely on auditory information to guide their companions in the process of forming groups. Pedestrian group behavior can be divided into three modes, the walking speeds of grouped pedestrians greatly depending on their spatial positions. By comparing and analyzing the walking speeds and evacuation times of pedestrians under different grouping modes, it is found that group behavior under zero-visibility condition reduces evacuation efficiency, while walking along the walls can improve evacuation efficiency. Subsequently, considering the movement characteristics of pedestrians in different group behavior modes, the influence mechanisms of auditory guidance and wall-following behavior on the evacuation process, a pedestrian evacuation model based on cellular automata under zero-visibility conditions is developed. Finally, the proposed model is validated by using experimental results, and simulations are conducted to analyze the influences of group behavior on the evacuation process under zero-visibility conditions. By comparing and analyzing the pedestrian movement trajectories and evacuation times during both the simulation and experiment, it is verified that the model can effectively reproduce the group evacuation processes of pedestrians under zero-visibility conditions. When auditory guidance errors are considered, pedestrians exhibit wandering behaviors in their movement trajectories. In the evacuation process, the greater the distance that pedestrians can perceive each other for grouping, the higher the probability of group formation is. As a result, groups are formed earlier, which will reduce the evacuation efficiency. This indicates that under zero-visibility conditions, group behavior exerts a negative influence on the evacuation process. This research lays a scientific foundation for formulating pedestrian evacuation strategies and schemes in similar scenarios.