Experimental study on pedestrian movement when facing an attacker in the presence of obstacles

The objective of research on pedestrian dynamics lies in investigating the characteristics of crowd movement and implementing measures to ensure crowd safety. Pedestrian groups facing an attacker, as a special type of movement group exhibiting unique interaction behaviors, hold significant importance in understanding their movement characteristics. In scenarios where pedestrians must evade an attacker, obstacles can function as tools for mutual evasion, effectively enhancing personnel safety. This paper presents an experimental design focusing on motion interactions between pedestrians and attackers in the presence of obstacles. By adjusting the height of obstacles, the experiment controls visibility between pedestrians and attackers, while obstacle length varies from 1.6 m to 6.4 m in 1.6 m increments. Results demonstrate that when obstacles are present, pedestrians preferentially utilize them and tend to make more effective use of long and low obstacles in their interactions with attackers. Finally, this study delineates crowd motion modeling principles in this experimental scenario—specifically addressing how perceived risk is assessed by crowds when obstructed by high or low obstacles—and investigates exit selection behavior among pedestrians, thus laying groundwork for modeling pedestrian movement in complex scenarios involving an attacker.