Risk Reduction Strategies against Terrorist Acts in Urban Built Environments: Towards Sustainable and Human-Centred Challenges

Abstract

Terrorist impacts have been increasing over time in many countries, being one of the most significant threats for the Built Environment (BE), intended as a network of open spaces (streets, squares) and facing buildings, and their users. Such risk is affected by a combination of strategic functions and crowd conditions. This work traces, for the first time, the state-of-the-art consolidated Risk Mitigation and Reduction Strategies (RMRSs). Solid RMRS regulatory frameworks from all over the world are collected. The results show how classification criteria distinguish them by attack targets and typologies, effectiveness over time/space, and physical implementation versus management-based deployment. Nevertheless, these criteria seem to be too fragmented, failing in pursuing RMRSs selection in a holistic outlook. Thus, a new classification adopting the BE composing elements (physical elements, layout, access/surveillance systems, safety/security management) as key-factors is provided. Features, dependencies and coordination among them are discussed in a sustainability-based perspective, by showing how the main challenges for RMRSs’ design concern applicability, redundancy, and users’ emergency support. Safety/security management strategies have the overall highest sustainability level and play a pivotal role with respect to the other BE composing elements, which should be planned in reference to them. In addition, a human-centred approach (individuals’ interactions with BEs and RMRSs) will also be needed. These results will support efforts to include simulation-oriented approaches into RMRSs selection, effectiveness and feasibility analyses.

European Cities Prone to Terrorist Threats: Phenomenological Analysis of Historical Events towards Risk Matrices and an Early Parameterization of Urban Built Environment Outdoor Areas

“…All the documents aim to manage all the disaster phases-Prevention, Mitigation and Security-introducing specific rules for the goals. Despite their multiplicity in each area, some specific contact points can be read among them [32]:…”

“…In this case, the index describes both the presence of preventative solutions in the urban BE (e.g., access control, heavy barriers) and the capacity to be efficient in the specific Attack Type (e.g., vehicles or cold steel) [48][49][50][51][52]. Here, all urban physical elements defined as mitigative, as well as geometric features of accesses, could be included in the assessment [32]. Due to that, in this index, we included all the physical elements included in the Outdoor Areas, as well as along the frontier.…”

A survey form for the characterization of the historical built environment prone to multi-risks

“…In Section 4 the median value was 15, with a minimum for Ostuni (12) and a maximum for Narni (20). Finally, section 5 showed a median of 8, with a minimum for Matera (7) and a maximum for Narni (10).…”

“…The value of these elements largely depends on the specific risk, the critical issues related to the functions they contain, and the use of such spaces made by users (e.g., becoming catalysts of attendance) [3]. Consequently, the safety conditions must be assessed by taking into account the interactions between different aspects: (i) morphological and constructive characteristics of the external spaces and the buildings facing them; (ii) their intended use and the variable presence of users over time both in the external areas and in the internal environments; (iii) the combined impacts of disastrous events on emergency and evacuation conditions, which essentially depend on the potential damage level for each risk [8]- [10]. Similar to other fields, such as urban energy behavior, these characteristics represent a higher level of building behavior: a meso-scale performance.…”

How Could Increasing Temperature Scenarios Alter the Risk of Terrorist Acts in Different Historical Squares? A Simulation-Based Approach in Typological Italian Squares

“…A terrorist act in a public open space such as a historical square could imply that users have to evacuate the space where they are initially placed, especially if no protection-inplace measures could be performed [19][20][21][22]. In this case, users placed outdoors should leave the square and move towards the linked streets [23][24][25].…”