Digging into California's autonomous vehicle requirements shows three key functions required for all AVs including:
Communication - between the vehicle and a remote operation
Collision - information to be displayed in the case of an accident or law enforcement activity
Equipment - either standard controls such as a steering wheel, brakes, etc. or an exception
Read more here:
The manufacturer shall also certify that the vehicle complies with all of the following:
(1) A communication link between the vehicle and the remote operator, if any, to provide information on the vehicle's location and status and allow two-way communication between the remote operator and any passengers, if applicable, should the vehicle experience any failures that would endanger the safety of the vehicle's passengers or other road users while operating without a driver.
(2) The ability to display or transfer vehicle owner or operator information as specified in Vehicle Code section 16025 in the event that the vehicle is involved in a crash, collision, or accident or if there is a need to provide that information to a law enforcement officer for any reason.
(3) Any vehicle that is not equipped with manual controls for completing the dynamic driving task, such as a steering wheel, brake pedal, and accelerator pedal, complies with all applicable Federal Motor Vehicle Safety Standards, or the manufacturer provides evidence of an exemption that has been approved by the National Highway Traffic Safety Administration.
Source: 13 CA ADC § 228.06.