There have been multiple times where, despite my best efforts to pay attention, I couldn't even see a traffic altering incident in front of me. The car in front of me, which was the only one I could see, did not prepare me quickly enough. Now, I didn't crash, but an advanced warning system can LIDAR/whatever under cars to see many cars ahead, warning me if three cars ahead are traveling at 0mph and I'm traveling at 70mph.

Of course, safe driving distance is important there - I'm not claiming otherwise. It was my safe distance that made it possible for me to stop. This is entirely besides the point though, as my human senses were entirely letting me down in that situation.

There's actually a good video of almost that exact situation by.. I think it was a Tesla. It started beeping with little visible reason why. Turns out, the traffic two cars ahead was at a stand still.

I can see what you're saying about automation, but I still think it would be a net gain in most scenarios. Though, I imagine it would be best to let people turn that off, but keep warnings intact.

Though eventually that hypothetical car behind you will also have autonomous breaking, so it'd be fine. It's just a matter of getting adoption rates high enough.

Then the crash would be the fault of the car following closely.

If you slam the brakes in front of a car for no reason and they rear end you, you are most definitely at fault.

At least in my state, you're supposed to allow something like a minimum of 4 seconds or some length of space between you and the car you're behind. The argument is that the car rear ending you should have been far enough behind to stop.

Effectively, if you get into an accident with a car infront or to the side, you aren't at fault when the guy right behind you hits you too.