The effect of rescue behavior for crowd evacuation via modified social force model

The modeling of rescue behavior is an important topic in pedestrian evacuation dynamics. In order to study rescue behavior for the injured pedestrian, a modified social force model is proposed to simulate crowd evacuation through considering the rescue attraction force and different movement mechanisms (e.g., other pedestrians’ avoidance of the rescuers and the injured individuals during the rescue process). The interaction rules between the rescuer and the injured individual are established to describe rescue behavior. A comparison is conducted on the impacts of with or without rescue behavior on evacuation efficiency. The influences of the position distributions and the number of rescuers, the avoidance strength, the rescue time and the distribution of injured pedestrian on evacuation dynamics in a hall are investigated. And the typical spatiotemporal dynamic characteristic during the evacuation process is also discussed. The simulation results show that considering the rescue behavior will reduce the total evacuation time evidently. The evacuation efficiency is the highest when the rescue is located in the center of the hall wall and away from the exit. Furthermore, the shorter the rescue time, the higher the evacuation efficiency, and the avoidance strength plays an important role on evacuation efficiency. In particular, an interesting self-organization phenomenon that the formation of a local rescue channel between the rescuer and the injured individual is discovered. Comparing to one rescuer, multiple rescuers can effectively improve evacuation efficiency. This study can provide a theoretical guidance for fast and safe rescue behavior in emergency situations.