A Simulation Study of Exit Choice Based on Effective Throughput of an Exit Area in a Multi-exit Evacuation Situation

To individuals evacuating, many multi-exit environments do not allow visibility of all the exits due to line-of-sight constraint. In addition, the environment can be dark or smoky, not allowing visibility to even a single exit. In such a situation, given that each individual in the crowd is accompanied with a helping device globally connected with a central server, a ´directional guidance´ towards an optimal exit is a real possibility. In this context, the ´occupant density´ around exits (within a static `exit area´) has been used in conjunction with the corresponding distances to devise a probabilistic strategy for optimal exit suggestion. In this paper, we related the exit area with the level of visibility of the environment (the more the visibility, the more the exit area and vice versa). In this way, a more realistic human-behavioral model is implemented in which an individual viewing (seeing) an exit would always direct towards that exit, irrespective of the directional guidance provided. When an individual is not at any of the exit areas (not viewing even a single exit), a directional guidance is provided assuming that the individual is adhering to it. Additionally we used the measure of ´effective throughput´ instead of occupant density, in conjunction with the corresponding distances. Through simulation results, we found a marked improvement in the evacuation time, when effective throughput was modeled instead of occupant density.