Pedestrian flow through exit: Study focused on evacuation pattern

Abstract

Experiments were conducted on the evacuation rate of pedestrians through exits with queued and random evacuation patterns. The experimental results showed that the flow rate of pedestrians was larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculates based on the minimum evacuation clear width for every 100 persons, which assumes that the pedestrians pass through the exit in one or several queues, is conservative. Compared with the queued evacuation experiments, the number of people crossing the exit simultaneously was greater in the random evacuation experiments, and the time interval between the front and rear rows of people was shortened in large-exit conditions when pedestrians evacuated randomly. The difference of flow rates with the queued and random evacuation patterns is related to the surplus width of the exit that greater than the total width of all containable people streams. Two dimensionless quantities were defined to explore this relationship. It was found that the difference in flow rates with the two evacuation patterns was stable at a low level when the surplus width of the exit was no more than 45% of the width of a single pedestrian stream. There was a great difference in flow rates with queued and random evacuation patterns in scenarios with larger surplus width of the exit. Meanwhile, the pedestrians were extraordinary crowding at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously was greatly exceed to the containable level. Therefore, the surplus width of exit should be limited especially in the narrow exit conditions, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.