Exploring asymmetric and symmetric pedestrian merging dynamics: Macro parameters and micro behavioral adaptations from single-file experiment

Pedestrian merging flow is a critical aspect of urban mobility, shaping movement efficiency and safety in complex environments. Collective crowd behaviors are induced by complex local interactions among individuals. For a better understanding of pedestrian merging dynamics, it is necessary to further explore microscopic individual adaptations during the merging process as well as their potential impacts on macroscopic movement patterns that affect merging performance. This study conducts controlled experiments to investigate pedestrian merging behaviors in T-shaped single-file scenarios, comparing both asymmetric and symmetric layouts (differing in flow directions) under varying flow and speed levels. Macroscopic parameters (e.g., average velocity, merging path distance) and microscopic parameters (e.g., lateral deviation, headway distance, stepping characteristics) are analyzed, and the interconnections are discussed. Key findings reveal that the inconsistent upstream velocity adaptation could affect merging velocity, where a faster velocity decay and shorter adaptation time result in lower merging velocity. Variability in upstream lateral deviations contributes to discrepancies in merging paths, with greater lateral deviation leading to more pronounced merging path reductions. It is inferred that velocity adaptation is linked to deceleration strategies involving stepping dynamics (e.g., step length, step frequency), while lateral deviation originates from pedestrians’ preferences for the shortest-distance and right-side bias. Furthermore, a negative correlation is identified between the stability of lateral deviation and velocity decay in both symmetric and asymmetric layouts. Those results address specific correlations between macro parameters and micro behavioral adaptations during the merging process, which might create disparities of movement states and induce latent higher density and delays. This work provides insights into pedestrian merging behaviors from a new perspective, with applications in enhancing pedestrian flow designs and safety management strategies. © 2025 Elsevier B.V.