Modeling and simulation analysis of crowd evacuation behavior under terrorist attack

Abstract

This paper explores the evacuation behavior of crowds during terrorist attacks. We extend a floor field model for a simulation of dual-role crowds in a three-dimensional (3D) space. In this model, pedestrians can bypass obstacles and move to target positions when avoiding attackers. An attacker can bypass obstacles to pursue target pedestrians. In addition, pedestrians and attacker have their own field of view models. In the model, obstacles obstruct the evacuation route of pedestrians, causing pedestrians to fail to escape the attacker in time and be injured or killed. In addition, obstacles also play a protective role for pedestrians, because obstacles obstruct the attacker’s pursuit route, and especially high obstacles also block the attacker’s view. We conducted 300 experiments to study the effects of obstacles on the evacuation of pedestrians under threat of attack. The following conclusions are drawn: (1) A single obstacle in front of an exit is more conducive to evacuation than no obstacle, (2) higher-density obstacles can better protect pedestrians from being chased by attackers, and (3) the direction of the aisle formed between obstacles should be consistent with the direction of the exit so that pedestrians can be evacuated more efficiently to reduce the death toll. We discovered two interesting phenomena, namely, circle and dispersion, which help to explain why fewer deaths occur in the presence of high-density obstacles.