Physics of low-speed human movement

Existing research on traffic and pedestrian flows has mainly focused on high-speed mobility data with average speeds above 1 m/s. However, the dynamics of low-speed movement, largely driven by social interactions, remain underexplored. In this study, we collected high-resolution spatiotemporal data on the movement of preschoolers in four distinct classroom and playground settings. Within the low-speed domain (average speed <1 m/s), we identified two novel social phases in children's movement: a gas-like phase characterized by free movement, and a liquid-vapor coexistence-like phase characterized by the formation of small social groups. Furthermore, analysis of peer interactions revealed a transition from ferromagnetic-like alignment to antiferromagnetic-like behavior. We propose a sophisticated potential that models the forces shaping these alignments. Our framework accurately reproduces the observed patterns, providing deep insights into the mechanisms governing collective behavior in low-speed human movement. These findings enhance our understanding of how social interactions influence movement and have broad implications for behavioral science, epidemiology, and active-matter systems.