A self-driving car, also known as an autonomous vehicle (AV), driverless car, or robo-car is a vehicle that is capable of sensing its environment and moving safely with little or no human input.

Self-driving cars combine a variety of sensors to perceive their surroundings, such as radar, lidar, sonar, GPS, odometry and inertial measurement units. Advanced control systems interpret sensory information to identify appropriate navigation paths, as well as obstacles and relevant signage.

Possible implementations of the technology include personal self-driving vehicles, shared robotaxis, connected vehicle platoons and long-distance trucking. Several projects to develop a fully self-driving commercial car are in various stages of development. Waymo became the first service provider to offer robotaxi rides to the general public in Phoenix, Arizona in 2020, while Tesla has said it will offer subscription-based “full self-driving” to private vehicle owners in 2021. Furthermore, the autonomous delivery company Nuro has been allowed to start commercial operations in California starting in 2021.

Autonomous means self-governing. Many historical projects related to vehicle automation have been automated (made automatic) subject to a heavy reliance on artificial aids in their environment, such as magnetic strips. Autonomous control implies satisfactory performance under significant uncertainties in the environment, and the ability to compensate for system failures without external intervention.

One approach is to implement communication networks both in the immediate vicinity (for collision avoidance) and farther away (for congestion management). Such outside influences in the decision process reduce an individual vehicle’s autonomy, while still not requiring human intervention.

Wood et al. (2012) wrote, “This Article generally uses the term ‘autonomous,’ instead of the term ‘automated.’ ” The term “autonomous” was chosen “because it is the term that is currently in more widespread use (and thus is more familiar to the general public). However, the latter term is arguably more accurate. ‘Automated’ connotes control or operation by a machine, while ‘autonomous’ connotes acting alone or independently. Most of the vehicle concepts (that we are currently aware of) have a person in the driver’s seat, utilize a communication connection to the Cloud or other vehicles, and do not independently select either destinations or routes for reaching them. Thus, the term ‘automated’ would more accurately describe these vehicle concepts.

As of 2017, most commercial projects focused on automated vehicles that did not communicate with other vehicles or with an enveloping management regime. EuroNCAP defines autonomous in “Autonomous Emergency Braking” as: “the system acts independently of the driver to avoid or mitigate the accident.” which implies the autonomous system is not the driver.