How simple behavioural modifications can influence evacuation efficiency of crowds: Part 2. Physical movement of individuals

In the context of evacuating crowded spaces during acute crises, every second is pivotal and can be the determinant in life-or-death situations. It is, therefore, important to explore and implement any measures or interventions that could streamline and expedite the evacuation process in such scenarios. This study aims to explore how the modification of individual behaviours can be leveraged to improve the efficiency of crowd evacuations, with a specific focus on the physical aspects of movement. We examine three crucial elements of physical movement: behaviours at bottlenecks, the initiation time of individual movement, and the pace of movement. A series of dedicated experiments, each tailored to one of these behavioural aspects, has been conducted. In these experiments, the behaviour of interest is modified incrementally within the crowd, with increases of 20% at each stage. This methodology allows for a detailed assessment of system efficiency at varying levels of instructed behaviour adoption/injection. The findings reveal that changes in each aspect of physical movement significantly influence overall efficiency. Most notably, the relationship between the uptake and increase in efficiency is nearly linear, and the rate of efficiency increase does not notably diminish with uptake, unlike interventions pertaining decision-making aspects of behaviour. This suggests that behavioural interventions targeting physical aspects of movement will likely yield higher efficiency returns. Moreover, in comparison with a related study focusing on decision-making aspects of evacuation behaviour, this research observes that modifying physical aspects of behaviour is generally more straightforward. The success rates of individuals in implementing physical movement instructions are higher, and the impact on the system is more pronounced than that observed in decision-making modifications. These results provide insights for developing simple, actionable instructions that can be effectively communicated to the public. These instructions can be disseminated as part of training and education programs or even provided on the spot during an evacuation.