The "world's first" driverless buses could launch in Edinburgh by spring after a successful trial of the self-driving vehicles.
The buses are operated by Stagecoach who are aiming to put five of the automated vehicles in service between Fife and Edinburgh.
Sensors on the buses allow them to run on pre-determined routes without a driver needing to control them.
They have undergone trials at a depot as well as track testing and virtual simulation.
The first road test has now been carried out with a group of volunteers becoming the first in the UK to travel on a full-size and self-driving bus on a public road, the BBC reports.
The passengers were taken on a single-decker bus over the Forth Road Bridge near Edinburgh.
One of the passengers, Fleur Dijkman, said: "I wasn't worried at all about it. You wouldn't know the difference between this and a normal bus from the driving."
Stagecoach said the test was successful and are hoping to launch the service, which is part of the CAVForth project, to the public by spring.
The first route will go from the Ferrytoll park-and-ride in Fife to the Edinburgh Park train and tram interchange — a 14-mile journey through mixed traffic going up to 50mph.
The buses will have the ability to carry up to 10,000 passengers a week.
Stagecoach has said that "for peace of mind" each of the vehicles will have a trained safety driver on board to monitor the system when in full operation, but they won't be required to touch the controls while the vehicle is in autonomous mode.
They said that the buses are designed to be safer than most human drivers, adding: "At Stagecoach, safety is our top priority, and this trial service is no different.
"We follow the latest government regulations and standards around autonomous vehicle technology. We have had our formal ‘Safety Case’ audited by independent experts. For peace of mind, we will also always have a safety driver behind the wheel monitoring the system and ready to take control.
"With the ability to see 360°, react faster and see further in bad weather, all while being risk-averse and not getting tired or distracted, the technology is designed to be safer than even the most experienced human drivers."
The CAVForth project is being run by Stagecoach in partnership with Fusion Processing, Alexander Dennis, Transport Scotland, Napier University and Bristol Robotics Lab.
It's expected to cost around £6.1million and is part-funded by the UK government's Centre for Connected and Autonomous Vehicles.
Business Secretary Grant Shapps said: “In just a few years’ time, the business of self-driving vehicles could add tens of billions to our economy and create tens of thousands of jobs across the UK. This is a massive opportunity to drive forward our priority to grow the economy, which we are determined to seize.
“The support we are providing today will help our transport and technology pioneers steal a march on the global competition, by turning their bright ideas into market-ready products sooner than anyone else.”
Ivan McKee, the Scottish government's business minister, added: "This is another hugely significant step forward for the CAVForth project that brings us closer to these autonomous vehicles entering service."
