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.

本研究调查了一项为老年人提供免费地铁出行的交通政策如何影响他们的出行行为。它通过确定老年人免费过境政策对更广泛的旅行行为的因果影响，改进了之前的研究。本研究使用回归不连续性研究设计，调查乘坐免费地铁的资格（65 岁阈值）如何影响韩国首尔大都市区老年人的出行行为。结果表明，老年人免费地铁政策增加了地铁出行次数，部分替代了其他交通方式出行。具体而言，65 岁时地铁出行次数的离散跃升取代了一些汽车出行，并有助于显着减少家庭车辆拥有量。然而，地铁票价豁免资格对社交/休闲旅行的相关结果没有统计上的显着影响，尽管它确实对家庭收入水平的积极旅行产生了不同的影响。除了为具有类似政策的城市提供宝贵的经验外，这项研究的结果还为当前关于韩国免费地铁政策的辩论提供了信息。