Behavioral-based multi-risk mitigation in historic squares: applying the BE S2ECURe approach to Piazza dell’Odegitria, Bari

Risks due to air pollution and heatwaves are increasing in historic city centers, slowly affecting communities’ behaviors in normal use of outdoor spaces. In this context, historic squares are the most relevant scenarios, due to users’ attraction according to cultural, social and leisure activities, and to morphology. Squares are also prone to sudden events implying evacuation, like terrorist acts, being ideal targets for perpetrators. The design of mitigation strategies should jointly consider all these risks and include users’ behaviors as a fundamental driver to assess strategies effectiveness. The BE S2ECURe project developed a behavioral-based method to evaluate mitigation strategies effectiveness in squares, from single and multi-risk standpoints, demonstrating their capabilities in idealized scenarios. This study hence aims at showcasing this method on Piazza dell’Odegitria (Bari), for heatwaves, air pollution and terrorist acts. Starting from an inventory assessed in typological scenarios, mitigation strategies are selected depending on their compatibility with heritage features and square uses. Behavioral simulations in single and combined events (i.e. heatwaves altering users’ exposure to terrorist acts) are performed using validated BE S2ECURe tools, in pre and post-retrofit scenarios. Comparisons are then performed organizing simulation outputs into BE S2ECURe indicators. Results show that, considering single strategies, engineered planters can reduce multi-risk up to about 13%, mainly acting on terrorist act evacuation and users’ protection. If overlapping these effects to cool pavement implementation, multi-risk reduction slightly improves (-14%) but effects to SLODs can be achieved, thus suggesting the advantages of redundancy solutions. The showcase demonstration of method capabilities confirms how decision makers could exploit the approach for preliminary mitigation strategies analysis.