Autopilot is not an implementation of self-driving cars... You have a completely wrong understanding of this system.
It's basically cruise control that has some lane keeping abilities. If you put your (non-TACC) car in cruise control on the freeway and then ignored everything around you, you will rear end someone, and it's not cruise controls fault. If you put a lane-keeping assist car (like Tesla or others) and completely ignored the road, it will crash eventually. AutoPilot is cruise control with some lane keeping abilities, it is not self-driving. You choose when to activate it (just like cruise control), and every single time you do it tells you to pay attention and keep your hands on the wheel.
It's basically cruise control that has some lane keeping abilities. If you put your (non-TACC) car in cruise control on the freeway and then ignored everything around you, you will rear end someone, and it's not cruise controls fault. If you put a lane-keeping assist car (like Tesla or others) and completely ignored the road, it will crash eventually. AutoPilot is cruise control with some lane keeping abilities, it is not self-driving. You choose when to activate it (just like cruise control), and every single time you do it tells you to pay attention and keep your hands on the wheel.