Exploring the causal impact of transit fare exemptions on older adults' travel behavior: Evidence from the Seoul metropolitan area

This study examines how a transportation policy enabling free subway travel for older adults affects their travel behavior. It improves upon previous research by identifying the causal effects of a fare-free transit policy for older adults on a wider range of travel behavior. Using a regression discontinuity research design, this study investigates how eligibility for fare-free subway rides (the age-65 threshold) influences travel behavior among older adults in the Seoul metropolitan area, South Korea. The results show that the fare-free subway policy for older adults increases the number of subway trips, which partly replaces trips by other transportation modes. Specifically, a discrete jump in the number of subway trips at age 65 replaces some auto trips and contributes to a significant reduction in household vehicle ownership. However, eligibility for the subway fare exemption has no statistically significant effects on outcomes related to social/leisure trips, although it does have varying impact on active travel by the level of household income. In addition to offering valuable lessons for cities with a similar policy, the findings of this study inform current debates on the fare-free subway policy in South Korea.