Investigating collective escape behaviours in complex situations

• Crowd behaviours under normal and panic conditions are substantially different.
• Data on collective egress under panic conditions are rare.
• Two series of experiments were conducted with panicking ants.
• Angled pathways can have significant impacts on collective crowd behaviours.
• Crossing and merging configurations can create dangerous stop and go waves.

Many different forms of complex pedestrian crowd behaviours, such as turning, crossing and merging, that could be critical under emergency and high density conditions can be identified in major public infrastructures. Scarcity of human data on panic has made it extremely difficult and challenging to model crowd dynamics in these complex situations, particularly under emergencies. Although previous crowd disasters in the past have highlighted that these different movements are crucial in panic, there are no comprehensive studies aimed at understanding and capturing these phenomena under panic conditions. In this study we utilise data collected through experiments with panicking ants in order to investigate the impacts of complex configurations such as turning, crossing and merging on the collective egress of crowds. Results suggest that, higher turning angles can reduce the speed at corners thereby reducing flow rates significantly, and crossing and merging configurations can create stop-and-go waves in upstream that can result in stampedes and crushing. These empirical studies could be beneficial for calibration and validation purposes of explanatory models and contribute to the development of effective evacuation strategies and design solutions for public buildings and urban environment.