Fare-free subway eligibility and older adults’ traffic safety: Evidence from Seoul, Korea

Population aging is reshaping urban mobility and intensifying concerns about older adults’ traffic safety in many countries. Although prior studies show that transit fare subsidies can change older adults’ travel behavior, it remains unclear whether these changes translate into improved traffic safety. Focusing on Seoul, this study examines changes in age-specific crash rates around the eligibility threshold for South Korea’s fare-free subway policy, which grants free subway rides to adults aged 65 and older. Using a regression discontinuity design, the analysis estimates discontinuities in neighborhood-by-age crash rates at the age-65 eligibility cutoff. The results indicate discontinuous declines in both driver-involved and non-motorized-user-involved crash rates at the cutoff. Supplementary travel survey evidence suggests that the decline in driver-involved crashes may reflect a shift from private car use to subway travel, an interpretation also broadly consistent with the comparable reductions observed in at-fault and non-at-fault driver crashes. For crashes involving non-motorized users, the decline at the age-65 cutoff is not accompanied by a reduction in walking or cycling trip frequency and is concentrated in crashes involving drivers younger than 65. Taken together, these findings indicate that fare-free subway eligibility is associated with improved traffic-safety outcomes for older adults both as drivers and as non-motorized users, highlighting the importance of considering traffic safety in evaluations and reforms of age-targeted transit fare policies.