My 2 cents
OK, so a little background on this driver. He had complained about the car's behaviour multiple times at this exact spot and yet didn't appear to have learned that the software wasn't able to cope. The particular location had previously been hit by another car so the attenuator was already crushed which made this much worse. CalTrans hadn't fixed it after the previous crash. 101 is also quite a light road surface based on when I used to drive along it and the markings are often faint to non-existent so for a human driver it can be tricky as others have noticed. Add to that the speed of the traffic along there, how close together people drive leaving very little room to actually see the road and react. Basically, we have a driver who wasn't paying attention (observed by other road users to be looking in his lap and not looking at the road), had experienced problems at this point in the road previously, and on a road with poor markings, an already crushed attenuator and driving at speed close to other cars. Just an accident waiting to happen and it could just as easily have been someone in any car running on cruise control and not properly paying attention. But lets place the blame on autopilot rather than the driver who was actually responsible here. Autopilot is known to be twitchy under tricky conditions and just is a driver assistance package but while it gets better with each release it isn't self driving so the meat sack at the wheel needs to pay attention.