Small group behaviors and their impacts on pedestrian evacuation

A modified social force model is proposed in this paper to simulate the small group behaviors and their impacts on pedestrian evacuation. In each small group, there is one leader and the others follow the leader during the evacuation process. We define an exponential formulation of the group attractive force among the small group. Simulation results show that the small group behaviors will cause negative effects on pedestrian evacuation. We further consider the panic case. In this paper, the panic is assumed to be caused by the congestion and the panic index is defined by the density of the agent´s neighbors. Under the panic case, the agents crowd together and the evacuation efficiency becomes lower.