Free bus travel for the over-60s has made them happier and more active, according to the first study into its health impact.
The research will come as a major endorsement of the policy pioneered in Scotland 13 years ago.
It enables nearly 1.4 million people to travel virtually without restriction.
University College London found card holders were more likely to have a better quality of life, greater life satisfaction and fewer depressive symptoms than others.
The study, published in the Journal of Transport and Health, involved nearly 6,000 people in England, but its authors said the results were likely to be the same north of the Border.
Lead author Dr Sarah Jackson said: “Our research shows free bus travel offers clear benefits to older people’s health and wellbeing.
“It helps them to stay active and facilitates better contact with friends and family, which in turn have a positive impact on mental health. And because mental health has knock-on effects for physical health, maintaining wellbeing is also likely to help people stay physically healthy in later life, reducing the financial costs associated with an ageing population.”
Free bus travel for the over 60s and disabled and visually impaired people and their companions in Scotland is expected to cost nearly £214 million this year, compared to £159m in 2006.
It accounts for one third of Scotland’s 390 million annual bus journeys.
Ministers last year quashed fears the age limit would be raised, following a review.
Passenger watchdog Bus Users Scotland said free travel benefitted older people and kept some bus services going.
Acting director Greig Mackay said: “The Scottish concession card is an excellent scheme which enables older adults to live independent lives and go out socially, and access healthcare, which is crucial to many.
“The concession card also helps tackle social isolation as people are able to interact with others at bus stops and on the bus.
“This is especially prevalent in rural areas where the bus is a lifeline for many.
“Being able to use the bus for free has significant financial benefits for those on lower incomes.
“The Scottish bus industry is also very reliant on the scheme, as this helps keep services viable that might not otherwise be provided if it was not for the reimbursement element.”
Claire Haigh, chief executive of Greener Journeys, an industry body campaigning for bus use, said: “Our research has shown every £1 spent on the free bus pass delivers at least £3.79 in wider benefits for society, by helping older and disabled people lead more active lives and access their communities and local services.
“Protecting the free bus pass scheme ensures that we as a society will all continue to benefit from this vital investment.” Paul White, of the Confederation of Passenger Transport Scotland, which represents bus and coach operators, said: “These benefits apply to all bus passengers and demonstrate the value of not only funding the national concessionary travel scheme but more widely supporting the bus sector to enable patronage growth.”