Factors associated with transit fare savings through the integrated fare system: A spatiotemporal perspective

Implemented in Seoul, South Korea in 2004, the integrated public transit fare system allows passengers to make transfer trips up to four times without additional charges and with fare discounts. This study analyzes the spatiotemporal variability of the fare savings. To this end, one day's smart card data from a weekday in May 2023 were combined with demographic and transit infrastructure data at the administrative unit level. The results revealed that users could save approximately USD 0.9 per trip on average for transfer trips. Moreover, the Geographically and Temporally Weighted Regression modeling showed that key factors, such as travel distance, income level, and transit accessibility, had different effects on fare savings, depending on the time of the day and area. The fare savings due to the implementation of the integrated fare system were greater in areas with longer travel distances and lower income levels, suggesting enhanced socioeconomic equity. Moreover, they were greater in areas with low public transit accessibility, especially during the morning peak period. The research findings provide valuable insights for policymakers to optimize the public transit fare system, meet the needs of diverse populations within cities, and establish a more inclusive and sustainable public transit system.