Identifying spatiotemporal delay-prone stations in the Stockholm metro network using emerging hot spot analysis

On-time performance is consistently identified as one of the most important factors influencing passenger satisfaction in public transport. Understanding where delays tend to occur - and whether these issues are persistent, intensifying, or sporadic - can help operators more effectively mitigate their impact. This study aims to identify spatiotemporal delay-prone areas at the station level within the Stockholm metro network, using the emerging hot spot analysis (EHSA) framework. Specifically, it examines the locations of delay hot spots, investigates whether they change over time, and, if so, how those changes unfold. The results indicated that only a few stations were classified as persistent hot spots for at least one season of the year, those being Sundbybergs centrum and Västra skogen on the Blue Line of the metro network, and Rådmansgatan and Skogskyrkogården on the Green Line. No stations were classified as persistent hot spots on the Red Line. The majority of stations across all lines and seasons instead exhibited sporadic patterns or no pattern at all, suggesting that long-term delay issues are relatively uncommon. Additionally, above-ground sections of the Red and Green Lines were found to have a higher concentration of hot spots compared to underground sections.