When responsible for overseeing a multi-ton vehicle, I like to know how it will behave. Cruise control and lane assist I understand. I need to know which one is in control and how it will behave if they can respond differently.
I like how my 25-year-old Range Rover has neither of those. Power steering and ABS is all you get.
Technically it does have cruise control, but I've never worked out what kind of road conditions it would be useful for and until I replace a 25-year-old dry-rotted vacuum hose under the bonnet it's not going to control a damn thing.
There is no difference in behavior when switching from FSD to Autopilot or vice versa. And there is never any ambiguity about which is active because it is completely determined by road type which you're obviously aware of while driving.
Yes, FSD is essentially a complete rewrite of Autopilot which will soon replace it for freeway driving too. Autopilot has been available for many years and FSD is new. This accident could have happened years ago and is not evidence of any issue with the new FSD stuff.
They currently operate on disjoint sets of roads, so they can only be roughly compared, and in rough comparison they do not behave differently. Of course if operated on the exact same road (which, again, is currently impossible) their actions would not be the same in every detail, just as different humans or even the same human driving the same road multiple times wouldn't. But that doesn't mean that there's necessarily any consistent difference that would enable a driver to use the information of which one is active to improve their predictions of the car's behavior.
