Vehicles that can drive themselves for some or all of a journey, using cameras, radar and other sensors with software that decides how to steer, brake and accelerate. Many cars already help with steering or braking while a person stays responsible. A truly self-driving vehicle takes over that responsibility, which is a much harder legal and technical step.
Technical view
The usual scale is SAE International’s J3016 (SAE was the Society of Automotive Engineers), with levels 0 to 5: up to level 2 a human drives and supervises, at level 3 the system drives but may ask a human to take over, and levels 4 and 5 need no human fallback, within a defined operating domain or anywhere. The software spans perception, prediction, planning and control. Rare edge cases, proving safety and liability are the hard problems. In Great Britain, the Automated Vehicles Act 2024 makes an authorised self-driving entity, not the person in the seat, responsible while a vehicle drives itself, once secondary legislation brings that regime into force.
Related
Part of AI Terminology Index, section: Modalities and Applications.