Evaluating and Mitigating Terrorist Risk in Historical Outdoor Open Areas Including User Factors

Terrorist risk in historical outdoor Open Areas (OAs), such as urban squares, is one of the most relevant conditions to explore for users’ safety, considering the attractiveness of these public outdoor spaces and their architectural, morphological and use-related features. Risk assessment tasks should be linked to risk mitigation analysis to support decision-makers in understanding which most probable terrorist threats and related effects could appear and how resilience-increasing strategies could be implemented while pursuing heritage preservation and ease of application. To this end, user factors in terms of behaviours in pre-emergency and evacuation conditions should be included, indeed. Nevertheless, structured frameworks to this end seem to be still lacking. This work proposes a novel, sustainable, user-centred framework for risk assessment and mitigation analysis to be applied in historical OAs such as squares. The framework relies on a simulation-based approach and incorporates tools validated within the BE S2ECURe project for scenario creation (preferring quick-but-reliable approaches) and evacuation process analysis, incorporating users’ behaviours. The framework is showcased on a relevant historical square, by defining and simulating pre and post-retrofit scenarios. In particular, mitigation strategies aimed at emergency management are mainly considered given their compatibility with preservation tasks. Results show how the framework can support local authorities in increasing resilience against terrorist threats.