Terrorist acts and pedestrians’ behaviours: First insights on European contexts for evacuation modelling

Europe has been subject to a significant increase in terrorist acts and their impact in recent years. In this context, real-world events pointed out how the pedestrians’ safety is significantly affected by the attacks and their consequences on the Built Environment. As already done for other Sudden-onset disasters, evacuation behaviours should be investigated to properly define risk-mitigation strategies, thus considering the impacts of main factors such as attack type, crowd level, pedestrians’ typologies, built environment conditions. This work tries to fill these literature gaps by innovatively proposing a behavioural database for terrorist acts according to consolidated methods. Firstly, videotapes of recent terrorist acts all over Europe are collected. Qualitative analyses reveal which behaviours are common with other kinds of emergencies and which seem to be more frequent, while quantitative analyses provide first structured data to simulate the pedestrians' evacuation, such as speeds and fundamental diagrams of pedestrians' dynamics. Comparisons with existing databases concerning other disasters are provided. Results highlight differences between behavioural outputs of qualitative and quantitative variables considering terrorist acts and other evacuation types. Thus, provided data could be used as input for developing and testing evacuation models in the contexts of terrorist acts.