서해선(대곡~소사) 개통 전후 접근성 변화량의 결정요인 분석: 네트워크 중심성 및 공간회귀 활용

초록

This study analyzes the impacts of the introduction of a new urban rail line on public transport network structure and station-level accessibility from a transport network perspective, using the opening of the Seohae Line (Daegok~Sosa) in the Seoul Metropolitan Area as a case study. While previous studies have focused on changes in ridership performance at individual stations or along specific lines, this study considers both network structural changes and the spatial diffusion of accessibility improvement effects. To this end, rail networks before and after the opening of the Seohae Line are constructed using GTFS-based actual operational information, and network centrality measures, including betweenness centrality, along with a 60-minute cumulative opportunity accessibility indicator, are derived. In addition, spatial regression models are applied to analyze the spatial dependence and spillover effects of accessibility changes. The results show that the opening of the Seohae Line restructured the public transport network in the western Seoul metropolitan area and generated accessibility improvement effects. In particular, areas accessible within 30 minutes to the new line and changes in betweenness centrality within the network had significant impacts on accessibility improvement, and these effects exhibited spatial spillovers to neighboring areas. These findings suggest that the impacts of urban rail openings extend beyond individual station areas and can reshape regional accessibility patterns by altering network connectivity and potential mobility opportunities. The results further indicate that accessibility change analysis may support metropolitan transport planning by informing network-level decision-making, including route evaluation, transfer hub consideration, and integrated feeder service planning. This study provides academic and policy implications by demonstrating urban rail opening effects at the network level through the integration of GTFS-based network analysis and spatial econometric models.

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