Individual-level exit choice behaviour under uncertain risk

Understanding human decision making during emergency evacuations is important. It is because decision making is crucial at each stage of the evacuation (e.g. route choice, exit choice, path finding, etc.). Previous studies have examined the influence of social interaction and environmental factors on exit choice. However, researches on the decision-making behaviour and risk attitude towards such selection at the individual level is still limited. To fill this knowledge gap, we designed a series of virtual evacuation scenarios to examine the exit choice behaviour and decision-making attitude in uncertainty risk scenarios in different smoke conditions. Data collection was implemented by an online stated preference survey. The results revealed a systematic and pattern preference in exit choice regardless of the decisions made by experienced evacuees. The weighted uncertainty risk for individuals was determined by considering the smoke height and smoke appearance frequency. The weighting function between the subjective and objective entities exhibited an S shape. In addition, the function was estimated using an empirical equation. A decision maker’s attitude towards uncertain risk in evacuation scenarios was observed to be a rank- and reference-dependent preference rather than being fully rational. The results of the experiments conducted in virtual environment well agreed with the cumulative prospect theory. This research demonstrates the feasibility of using virtual environment for evacuation experiment which can total avoid the risk of stampede while the individual decision-making behaviours can still be captured.