I disagree it's the person calling the car that would be responsible, but I can think of a very obvious group of people being held responsible for that. Who do you think should be responsible for such a situation?
I, realizing that I don't have infinite resources and intelligence turn said responsibility to a group of investigators that I hope has collective intelligence and resources much larger than my own to trace culpability. One would think the car manufacture is the most obvious answer, but every witch hunt in history had those same good intentions.
Maybe. There will be an investigation looking at things like. Did the user modify the car? Was the car modified by an unauthorized 3rd party? Was the car hacked?
Right now in AI things are relatively clear because it takes just massive amounts of power and compute to make anything remotely complicated. This barrier will fall as all other barriers in compute have fallen. Either via algorithm or hardware.
In our lifetime (unless you're rather old) we will see the relatively easy creation of self directing agents by actors with few resources. This breaks the standard concepts of liability where a single human actor rarely has the ability to create massive amounts of damages far beyond their means. The closest thing I can think of is an arsonist causing billions in damages, only in this case the fire has a will of it's own and can hide and spread around dark places on the internet.
The mental model you have is one that existed in the past and is broken now the future arrived. Bad analogies do not even begin to explain what is occurring.