Use of immersive virtual reality-based experiments to study tactical decision-making during emergency evacuation

Humans make their evacuation decisions first at strategic/tactical levels, deciding their exit and route choice and then at operational level, navigating to a way-point, avoiding collisions. What influences an individuals at tactical level is of importance, for modelers to design a high fidelity simulation or for safety engineers to create efficient designs/codes. Does an unlit exit sign dissuades individual(s) to avoid a particular exit/route and vice versa? What effect does the crowd's choices have on individual's decision making? To answer these questions, we studied the effect of exit signage (unlit/lit), different proportions of crowd movement towards the exits, and the combined (reinforcing/conflicting) effect of the sign and the crowd treatment on reaction times and exit choices of participants in an immersive virtual reality(VR) evacuation experiment. We found that there is tolerance for queuing when different sources of information, exit signage and crowd movement reinforced one another. The effect of unlit exit signage on dissuading individuals from using a particular exit/route was significant. The virtual crowd was ineffective at encouraging utilization of a particular exit/route but had a slight repulsive effect. Additionally, we found some similarities between previous studies based on screen-based evacuation experiments and our VR-based experiment.