A Model to Assess the Role of Spatial Urban Configurations on Crowd Evacuation Dynamics During Terrorist Attacks

Abstract

International audienceIn this article we focus on behaviour of population facing new forms of terrorism, such as the attacks perpetrated by sects, groups or "lone wolves". Terrorism acts are most often perpetrated in crowds, in frequented places or on public transport at rush hour. They give rise to diversified human reactions. One can observe behaviours of sideration, panic, flight and fight, mutual aid, etc. There are few data available to identify the dynamics of the displacements associated with these behaviours and to analyse the impact of spatial configurations on these dynamics. Based on the recently published Panic-Control-Reflex (PCR) model, we introduce a new model of weighted human behaviour in the context of urban terrorist attacks. This new Coupled Weighted PCR (CWPCR) model takes into account the role of spatial configurations on behavioural dynamics in a street and place network. It incorporates, via a bottleneck effect, the narrowness and the length of the streets, and thus the pressure and counter pressure of the crowd in dangerous and safe places. The numerical evacuation simulations highlight that, depending on their size, intermediate places modulate the dynamics and the speed of flow of the crowd as it evacuates to a safe place