Temporal Variation and Spatial Heterogeneity in Boarding/Alighting Patterns at Urban Railway Stations: Implications for Estimating Optimal Construction Scale—A Case Study in Seoul, South Korea

Urban railways have become a prominent mode of public transportation within cities owing to their connectivity with other modes of transport and environmental friendliness. Various policies, such as the expansion of metropolitan areas and the development of megacities, have further emphasized the pivotal role of urban railways. Consequently, more railway stations are expected to be constructed in developed cities. However, the temporal variation in boarding and alighting patterns at each railway station is often overlooked. Failing to account for this variation, specifically the differences in peak-hour concentration rates, in railway station design may cause increased conflicts among users owing to concentrated demands during specific time periods, exacerbating congestion and diminishing the appeal of the urban railway systems. Therefore, this study investigated the correlation between the temporal variation in boarding and alighting patterns and the attributes (location) of railway stations in Seoul, South Korea, and analyzed the spatial heterogeneity of this correlation. Initially, the factors influencing the peak-hour concentration rates in railway stations were identified using a linear regression model. Peak hours were defined as morning and afternoon peaks and boarding and alighting were differentiated to account for the directional aspects of temporal variations in boarding and alighting patterns. The correlation between boarding and alighting patterns and the attributes of railway station influence zones was determined, and a geographically weighted regression model was estimated to analyze the spatial heterogeneity of this correlation based on railway station location. The analysis results revealed that railway stations in the southeastern and downtown areas of Seoul exhibited varying impacts of station attributes on boarding and alighting patterns even when the station attribute influence zones were identical. The contribution of this study is to evaluate the priorities of railway projects and its corresponding transportation policies. Regarding the policy goal recently announced by the Korean government, “Achieving Commute Times in 30-min range,” our finding will provide a good measure of accessibility whether it succeeds or not.