Pedestrian single-file movement on stairs under different motivations

In this paper, we conduct a single-file experiment on stairs under two motivations, namely normal walking condition and fast walking condition at various densities. Totally four types of movements are analyzed and compared, namely normal walking-ascending movement, normal walking-descending movement, fast walking-ascending movement and fast walking-descending movement. Compared with the normal walking condition, in fast walking condition pedestrians move with higher velocity, which can be clearly observed in color-coded trajectories and time–space diagrams. We further make pairwise comparisons of density–velocity and headway–velocity relations for four types of movement, and critical parameters such as minimum headway, adaptation time, critical headway and free-flow velocity are extracted. It is found that the adaptation time is negatively correlated with free-flow velocity, indicating that pedestrians under higher movement motivation have a stronger ability to adapt their velocities. Besides, the values of time to collision are smaller for ascending movement than descending movement, apart from those at high density. In addition, we also analyze the following behavior through the relation between velocities of two adjacent pedestrians. The correlation analysis indicates that velocities are most correlated in fast walking-descending movement, and least correlated in normal walking-ascending movement. It is hoped that our study can be useful for the modeling of stair motion and the design of building stairway.