Agent-based modelling and simulation of elderly residents’ dynamic usage patterns in neighbourhood squares during summer

Understanding how elderly residents use neighbourhood squares is helpful for designing these public areas to maximize their usage and minimize heat exposure risks, especially given the global increase in heatwaves and initiatives for healthy aging in place. This study aims to explore the dynamic use of a neighbourhood square with multiple shade configurations by its elderly residents. In-situ observations and measurements in three squares in public housing estates in Hong Kong were conducted in hot summer days to learn the relationship between elderly users' usage behaviours and multiple driving factors, including outdoor thermal environment, level of social interaction, and different shade types. The relationship was then used to develop an agent-based model (ABM) to simulate the dynamic usage pattern in a square over a day. The result indicates that the dynamic usage pattern from 9:00 to 18:00 in a square emerges from interactions between elderly users’ behaviours and shade configurations, which can be reasonably estimated by the developed ABM. Based on the ABM simulation, shade configurations that cover 60 % of the square and create microclimates with a maximum mPET not exceeding 34.0 °C during summer days encourage square usage and mitigate heat-stress risks of elderly users. The prototype ABM enables the understanding of the complex usage pattern in a neighbourhood square and can potentially assist planning and optimization of shade configurations at the design/renewal stage.