Pedestrian ascent and descent fundamental diagram on stairway

Due to the interaction among individuals, pedestrian walking speeds in relatively dense crowds when descending and ascending stairs may present different features from a single pedestrian moving freely. Thus, to obtain a large range of densities, a series of single-file pedestrian movement experiments under laboratory conditions were performed. The trends of the fundamental diagram in a wide pedestrian density range for staircase movement are captured. Detailed features of pedestrian speed with the increase of pedestrian density, headway, and the influence of pedestrians' lateral sway are further discussed. It is found that with the increase of pedestrian density, the speed decrease rate varies. Meanwhile, the decrease of headway, leads to two speed regimes, i.e. free movement and linear constrained movement. We show that pedestrian speed can be described by counting the number of steps separating pedestrians in longitudinal direction. These enrichments can benefit pedestrian modelling and improve the evaluation of the evacuation performance of a staircase.