How Simple Hypothetical-Choice Experiments Can Be Utilized to Learn Humans’ Navigational Escape Decisions in Emergencies

Abstract

How humans resolve non-trivial tradeoffs in their navigational choices between the social interactions (e.g., the presence and movements of others) and the physical factors (e.g., spatial distances, route visibility) when escaping from threats in crowded confined spaces? The answer to this question has major implications for the planning of evacuations and the safety of mass gatherings as well as the design of built environments. Due to the challenges of collecting behavioral data from naturally-occurring evacuation settings, laboratory-based virtual-evacuation experiments have been practiced in a number of studies. This class of experiments faces the traditional question of contextual bias and generalizability: How reliably can we infer humans’ behavior from decisions made in hypothetical settings? Here, we address these questions by making a novel link between two different forms of empirical observations. We conduct hypothetical emergency exit-choice experiments framed as simple pictures, and then mimic those hypothetical scenarios in more realistic fashions through staging mock evacuation trials with actual crowds. Econometric choice models are estimated based on the observations made in both experimental contexts. The models are contrasted with each other from a number of perspectives including their predictions as well as the sign, magnitude, statistical significance, person-to-person variations (reflecting individuals’ perception/preference differences) and the scale (reflecting context-dependent decision randomness) of their inferred parameters. Results reveal a surprising degree of resemblance between the models derived from the two contexts. Most strikingly, they produce fairly similar prediction probabilities whose differences average less than 10%. There is also unexpected consensus between the inferences derived from both experimental sources on many aspects of people’s behavior notably in terms of the perception of social interactions. Results show that we could have elicited peoples’ escape strategies with fair precision without observing them in action (i.e., simply by using only hypothetical-choice data as an inexpensive, practical and non-invasive experimental technique in this context). As a broader application, this offers promising evidence as to the potential applicability of the hypothetical-decision experiments to other decision contexts (at least for non-financial decisions) when field or real-world data is prohibitively unavailable. As a practical application, the behavioral insights inferred from our observations (reflected in the estimated parameters) can improve how accurately we predict the movement patterns of human crowds in emergency scenarios arisen in complex spaces. Fully-generic-in-parameters, our proposed models can even be directly introduced to a broad range of crowd simulation software to replicate navigation decision making of evacuees.

Redefining the role of obstacles in pedestrian evacuation

“…Despite that this phenomenon must be confirmed by further experiments in which other obstacle diameters and shapes as well as more competitiveness levels are implemented, our work challenges the validity of most of the existent models in which there is always a given range of obstacle positions for which the flow rate improves (with more or less efficacy depending on the obstacle properties). This hints about the necessity of revisiting, for the case of highly competitive conditions, some numerical aspects (such as the route choice [41] at spatial scales smaller than one metre) and/or incorporating new ones (such as the individuals shape [42,43] and the preferred orientation in the displacement [44,45]). Moreover, we discovered that placing an obstacle in front of the exit reduces the magnitude and number of collective transversal displacements, suggesting that its implementation would be beneficial in preventing falls.…”

On the Boate Kiss Fire and the Brazilian Safety Legislation - What we can learn

“…It is expected that this knowledge must be more fully discussed, before another similar tragedy happen 27 27 The last great fire tragedy in a nightclub with a lot of similarities to Boate Kiss happened in Romania, still not addressed. To illustrate, the following points can be raised: what would be the real contribution of the air conditioning system in the scattering of the smoke; environmental variables and others can significantly influence the route-choices [47][48][49], then what are the influence of each one the collective and environmental factors that caused people to move toward the bathroom instead of the exit; how realistic can one deal with accessibility and disability's issues for an evacuations in non-adaptive behaviour situation associated to a high population densities in a nightclub?…”

‘Rationality’ in Collective Escape Behaviour: Identifying Reference Points of Measurement at Micro and Macro Levels

“…These are exit choice, local pathfinding, and step-taking modules. At the highest level of the modelling, we generate (i.e., probabilistically simulate) a choice of exit for each simulated agent [60][61][62][63] once they enter the main multiexit room. The choice is simulated from a multinomial logit model (see (1)) with five attributes (see (2)).…”