A fleet of buses fuelled by chip fat is taking to the roads of Ayrshire in a trial green transport project.
It is hoped the chip fat fuel will reduce emissions
Stagecoach's Bio-Bus scheme also offers a 20p discount for passengers who bring along their used cooking oil.
The scheme featuring the eight-strong fleet, which will run between Stewarton and Darvel, aims to cut harmful emissions by more than 80%.
The initiative will run for the next six months and operators hope it could roll out nationwide.
A spokesman for Stagecoach said: "Eight vehicles in Kilmarnock will run on 100% bio-diesel manufactured from used cooking oil and other food industry by-products, resulting in an expected 82% cut in CO2 emissions.
"Crucially, the bio-diesel is produced from tallow and used cooking oil, both of which are sustainable feedstock sources that do not involve the destruction of natural habits or compete with the human food chain."
For the first 10 minutes of the morning, the buses run on diesel until normal engine operating temperature is reached and then the system automatically switches over to bio-diesel, which powers the vehicles all day.
Passengers on the route are being given containers to collect fat
Households on the Stewarton route will receive a free container to recycle their used cooking oil and Ayr MSP John Scott welcomed the recycling prospects of the scheme.
He said: "I believe it's win-win for people who will be able to take their cooking oil along and have it turned into tickets."
The project has been set up in partnership with bio-diesel business Argent Energy, while East Ayrshire Council will support the recycling element of the project.