Aversion of pedestrians to face-to-face situations eases crowding

We conducted a numerical simulation of a crowd of pedestrians. Each pedestrian, modeled with three circles, has a shape whose long axis is perpendicular to the anteroposterior axis and is designed to move in a fixed desired direction, i.e., +x or -x. Pedestrians have friction at their surface, soft repulsion, and a back force to resist backward motion. In this study, we newly introduced an active rotation that captures the psychological effect of aversion to face-to-face situations. The numerical simulation revealed that active rotation induces the fluidization of the system, leading to the higher flux of pedestrians. To reveal the mechanism of the fluidization, we calculated the minimum principal stress for each pedestrian. Furthermore, we visualized force chains observed in the system by connecting the minimum principal stresses. We confirmed that the fluidization of pedestrians is due to the fragmentation of the force chains induced by the active rotation.