Background: Social engagement and social isolation are key determinants of mental health in older age, yet there is limited evidence on how public policies may contribute to reducing isolation, promoting social engagement, and improving mental health among older people. This study examines the impact of the introduction of an age friendly transportation policy, free bus passes, on the mental health of older people in England.

Methods: We use an instrumental variable approach that exploits eligibility criteria for free bus passes to estimate the impact of increased public transportation use associated with the policy on various measures of mental health, social isolation, and social engagement.

Results: Eligibility to the free bus travel pass was associated with an 8% (95% confidence interval [CI]: 6.4% to 9.6%) increase in the use of public transportation among older people. IV models suggested that using public transport was associated a 0.952 point (95% CI: -1.712 to -0.192) decline in depressive symptoms. IV models also revealed that public transport use was associated with a reduction in feelings of loneliness (ß: -0.794, 95% CI: -1.528 to -0.061), and with increases in volunteering at least monthly (ß: 0.237, 95% CI: 0.059 to 0.414) and having regular contact with children (ß: 0.480, 95% CI: 0.208 to 0.752) and friends (ß: 0.311, 95% CI: 0.109 to 0.513).

Conclusion: Free bus travel is associated with reductions in depressive symptoms and feelings of loneliness among older people. Transportation policies may increase older people’s social engagement and consequently deliver significant benefits to mental health.