The association between community-based transportation use and depressive symptoms among older adults in Japan

The electric vehicle, called Green Slow Mobility (GSM) promoted in Japan as an age-friendly mobility solution. While interest in GSM has grown, evidence of its health impact remains limited. In Matsudo City, community residents operated the GSM service, providing an example of community-led mobility support in an urban setting. We aimed to examine associations between GSM use and health-related outcomes among older adults in Matsudo City, Japan. We analyzed two-wave longitudinal data from GSM service areas. Our analytic sample included 4,080 adults aged ≥ 65 years who completed both 2022 and 2023. We defined GSM users as those who reported using GSM at least once per month. We treated depressive symptoms (GDS-15; 0–15) as the primary outcome and frequency of outings (0–6) and the number of social supports (0–4) as secondary outcomes. We applied augmented inverse probability weighting to estimate average treatment effects (ATE), adjusting for 13 baseline covariates including sociodemographic characteristics, health indicators, social participation, and baseline values of all outcome variables. GSM users reported fewer depressive symptoms (ATE = − 1.39; 95% CI: − 1.94 to − 0.83), higher frequency of outings (ATE = 0.60; 95% CI: 0.43 to 0.77), and had more social supports (ATE = 0.25; 95% CI: 0.12 to 0.38) than non-users. Our findings suggest that community-based transport systems such as GSM can enhance mental health and social well-being and may promote healthy aging in urban populations. Our results may inform policymakers seeking sustainable transport models that support both mobility and public health.