Examining the impact of different turning angles on the collective egress of crowds

Previous case studies of crowd disasters highlighted that collective human behaviors associated with common manoeuvres, such as turning movements, can be potentially dangerous particularly under emergency conditions. Therefore, proper consideration should be given when designing physical features such as angled or circuitous pathways at crowd-gathering places. A major gap in the knowledge is that no substantial research has examined crowding and turning-angle impacts on collective egress of crowds. In this study, to investigate the influence of turning angle on collective crowd behaviors, the authors utilize empirical data collected from human trials under normal walking conditions and from ants under panic conditions. Results obtained from analyzing empirical data from human trials suggest that higher turning angles (e.g., 60° or more) are inefficient in terms of significantly reducing the flow rates and velocities under normal/orderly evacuation conditions. This threshold angle could be reduced (e.g., up to 45°) under panic conditions, as verified with experiments with ants under panic conditions. These empirical studies are beneficial for calibration and validation purposes of the explanatory models and contribute to the development of effective evacuation strategies and design solutions for public buildings and urban environment