An extended model for crowd evacuation considering rescue behavior

Most evacuation processes require the presence of people outside the scene, such as firefighters, to assist the trapped individuals to evacuate. This paper establishes an extended model for crowd evacuation considering rescue behavior. In the model, rescuers enter from the exit, approach the hazard source, and search for the injured individual. According to the physical condition of the injured pedestrian, there are two rescue methods: supporting or carrying the injured persons on their backs. Persons trapped in a room are evacuated by walking or crawling depending on their health condition, and healthy persons will rescue the surrounding crawling and evacuated individuals with a certain probability. Simulation results demonstrate that during the evacuation process considering rescue behavior: (1) The presence of rescuers improves evacuation efficiency. When the number of rescuers exceeds a certain threshold, the efficiency of evacuation will begin to decline. However, the evacuation efficiency with rescuers is still better than when there are no rescuers. (2) Increasing the possibility of pedestrian mutual assistance can improve evacuation efficiency. However, the effect of pedestrian mutual assistance probability on evacuation has a critical value. (3) The greater the distance from the hazard source to the exits, the smaller is the effect of the hazard source on evacuation. (4) when the total width of all exits is the same, the evacuation efficiency of two exits is higher than that of a single exit. The model and overall simulation results can help to develop different evacuation strategies and improve search and rescue plans according to specific scenes.