Conflicts at an Exit in Pedestrian Dynamics

In this paper, we have detailedly studied the effect of conflicts on the pedestrian outflow through an exit. Pedestrians conflict each other at the exit, which is a bottle neck, when they evacuate from a room. The pedestrian outflow decreases when there are many conflicts. In the floor field model, which is a pedestrian model using cellular automata, the conflicts are taken into account by the friction parameter. However, the friction parameter is a constant and does not depends on the number of the pedestrians conflicting at the same time. We have extended the friction parameter to the friction function, which is a function of the number of the pedestrians involved in the conflict. The results of theoretical analysis using the friction function agree with the experimental results much better than using the friction parameter. We have also found that putting an obstacle in front of the exit increase the pedestrian outflow from our experiments. The friction function clearly explains the mechanism of the effect of the obstacle, i.e., the obstacle blocks a pedestrian moving to the exit and decrease the average number of pedestrians involved in the conflicts.