Two medical students have used their spare time during the pandemic to create a car-sharing app that can pay for renewable energy projects.
University of Birmingham students Daniel Chivers and Michael Trueman, both 22, designed it for medical students but hope to extend its use.
The app works out how much a passenger should pay and they can voluntarily contribute to environmental schemes.
Mr Chivers said he felt there was "a need" for the app.
"Trying to keep track... [of miles] is quite laborious. People don't know how much fuel costs because it's so difficult to calculate.
"[The app] makes sure drivers aren't making a profit," he said.
In March 2020, while in their third-year, the pair started to create Commute: Fuel Splitter after calculating the average medical student in Birmingham is required to travel over 3,000 miles a year for clinical placements.
Mr Trueman, from Scunthorpe, said: "There are a lot of eco-conscious students. You have to make drastic changes about how we live to minimise the impact on the environment."
Users of the app can input the car's fuel efficiency and the price of fuel, along with the starting point and destination to calculate the miles. The app also takes into account the car's miles-per-gallon.
On the basis of an individual's "personal miles", which would be 10 miles for a 20-mile journey shared with another person, the app suggests how much you should pay towards projects to offset the carbon emissions of your trip.
Planting trees, setting up a wind farm or adding solar panels to houses are some of the schemes, while the app company takes commission from its users' individual contributions.
About 200 students are on the app, but the pair would like it established in 10 universities by the end of the year.
They said they wanted "to make social change" and make personal petrol and diesel cars as sustainable as possible.
Not only have the pair been developing the app, they also took on medical work three years earlier than typically expected.
Mr Trueman said it had been "eye-opening" while working 45 hours a week in hospital during the coronavirus pandemic, in what was a period of "tremendous personal growth".
"Having responsibility at the time we did, it was difficult to shoulder at times," he said.
Mr Chivers, from Leeds, said when junior doctors were off sick, "we were the only option" to fill in.
"You're seeing stuff no-one is seeing... we're the ones calling their families and telling them what's happening.
"It's not something you'd expect as a medical student."
Source: BBC