An extended social force model considering the psychological impact of the hazard source and its behavioural manifestation

The hazard source is the essential cause for evacuations, and it has an impact on the psychological state of the pedestrians, which is further manifested in their behavioural patterns. This study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment, and to simulate the pre-evacuation delay time and a virtual repulsion force from the hazard source, controlled by its properties. The integration is validated with the results of the previous experiment, and subsequent simulations reveal 1) that the pre-evacuation delay time is the major contributor to the effects of the hazard source, 2) that the detour effect, generated by the repulsion force, significantly lengthens the evacuation time for sparse crowds, and 3) that a moderate (but not stronger) repulsion force near the bottleneck improves the efficiency to pass through it for dense crowds. (c) 2023 Elsevier B.V. All rights reserved.