Safety level of autonomous driving

SAE (Society of Automotive Engineers), the American Society of Automotive Engineers, defines the levels of automatic driving as follows:
Level 0: Fully manual driving, the system only issues warnings.
Level 1: The automatic system controls [steering] or [acceleration], and the driver must be ready to take over (intervene) the vehicle at any time.
As in scenario A, the driver controls the steering wheel by himself, and the automatic system throttles to maintain a set speed for cruise control (Cruise Control).
As in scenario B, the driver controls the steering wheel, automatic system throttle and brakes to maintain a varying speed, adaptive cruise control (ACC).
Level 2: The automatic system controls [steering] and [acceleration], and the driver must be ready to take over the vehicle at any time.
The driver's hand must touch the steering wheel to enter the automatic system.
Level 3: Autonomous driving under specific conditions when there is a driver.
The driver must take over within a certain period of time when the vehicle requests to take over.
Level 4: Autonomous driving under specific conditions without the driver.
Level 5: Unconditional autonomous driving