Egress Route Choice Modelling—Concepts and Applications

Most microscopic evacuation models offer the possibility to determine the individual egress route based on a shortest path criteria. This option has the advantage that the egress route is only depending on the building structure and can thus be calculated in advance. Yet there has to be the possibility for individual and dynamic adjustments depending on egress route load (avoid congestions), attractiveness of route alternatives or external influences like smoke spread if appropriate. However, care has to be taken that these adjustments do not lead to unrealistic counter flows or artificial blocking effects. Human egress behavior is triggered by a very complex interaction of perception, anticipation and fine-tuning of movement that can up to now only be modelled in a very approximative way on a large scale. The basic concepts of egress route choice modelling implemented in the microscopic evacuation model ASERI are presented together with case studies demonstrating the effect of certain egress route choice options on evacuation efficiency and calculated egress time. Emphasis is put on the mechanisms modelling avoidance strategies in case of congestion or in the presence of equivalent egress route options. Some of these mechanisms are dynamic, based on local occupant load and the local building environment and may involve non-deterministic rules.