A study of the role of forceful behaviour in evacuations via microscopic modelling of evacuation drills

Abstract

This paper reports on the microscopic modelling of evacuation drills through merging corridors carried out to gain further insight into the dynamics of pedestrian flows in an evacuation. A new pedestrian flow modelling package called PiXIE (ProXimity toolkit for Interacting Entities) was developed. It relies on a microscopic description of an evacuation at the individual level and is based on the so-called Social Force Model. It also implements one of its many modifications which includes the notion of respect between individuals and accounts for the fact that in the experiments participants tended to behave in a non-competitive way towards each other. The model was used to explain some of the experimental results, in particular the absence of the Faster Is Slower (FIS) effect. We show that the lack of the FIS effect in the original experiments was due to the lack of competitive behaviour rather than being an inherent characteristic of merging pedestrian flows. Our results corroborate earlier findings which showed that, in addition to speed, competitive pushing is indeed an essential factor in the occurrence of the FIS. From an emergency management perspective this implies that evacuees should seek to evacuate at a reasonably high pace while remaining calm and not pushing others in doing so. These results also highlight the critical importance of accounting for expected changes in human behaviour under the conditions of a real emergency situation versus evacuations conducted under controlled conditions.