We seem to be talking at cross purposes. I don't disagree that all types of interventions should be minimized. My only disagreement is that you wanted to use accident rates as a benchmark for interventions that included those that would not have led to accidents otherwise. For the most part, I agree with what you are saying.
As I noted above there are different issues with measuring the abilities of car. Clearly accident rate is the most important. Then there is legality .. does the car obey traffic laws (and know when they occasionally must be skipped). Then there is comfort .. does the car drive pleasantly for the occupants. Then there is accuracy .. does the car get you where you wanted to be?