Self-organization Phenomena in an Evacuation Flow

A cellular automaton (CA) model is used to simulate the pedestrian evacuation in a squared room with one exit. Two types of evacuees (cooperators and defectors) are considered in this model. Combined with the snowdrift game theory, the complicated interaction relations among the conflicting pedestrians are explored. The movement of pedestrians in conflicts depends on the average payoffs received from their neighbors, and the pedestrians change their strategies simultaneously according to a life like rule, which reflects rationality on pedestrians' judgements. It is found that there exist self-organization phenomena during the evolution process of evacuation. A series of numerical experiments are conducted to show these phenomena. Moreover, the simulation results indicate that moderate ratios of initial cooperators, coupled with relatively large cost of conflict, lead to short evacuation time.