[I wrote "tacc does sometimes see car in your lane and thimk you will drive around it. See th3 blue prius video. Where tracked car changes lanes to go into a turning lane revealing a stopped car in front of it. The tacc has to decide will the tesla follow the tracked car thus going around the stopped car? Or will it stay in this lane and thus need to stopbehind the stopped car?"]
TACC just doesn't work that way. TACC never assumes you are going to change lanes. In the video you are talking about TACC did not pick up the new target car that was stopped in the lane the Model S was travelling in, as the old target car was turning.
"TACC did not pick up the new target car that was stopped in the lane"
is ambiguous between:
1) TACC did not switch the target/following car to the car that was stopped in the lane (even though it may have sensed that something was there -- as it almost certainly did -- because it's right there!).
2) TACC did not sense (even as parked car or other fixed object of some kind) the car that was stopped in the lane.
I think what happened is Case 1 above. TACC *did* pick up the car that was stopped, just as it often picks up parked cars. But it didn't label it a target to be followed, and thus stopped, because it was projecting some other path, such as following an original tracked car which was driving around it.
This happens all the time when the Tesla doesn't screech to a halt when there are cars that are parked in a way just past two lanes merging into one where the merged lane is replaced with a lane of parked cars. TACC senses the stopped cars, but doesn't slam on the brakes each time because it predicts usually correctly, that parked cars shouldn't be followed but rather driven around.
This can cause problems when the driver is steering, and plots a different course than TACC (e.g., driver: I will stay in this lane and expect TACC to stop behind the new car in front of me vs. I will follow the currently tracked car and drive around that stopped/parked car directly in front of me and thus expect TACC to follow the other car (or even if there is no other car, simply know that I will be in the other lane) rather than stop behind a parked car).
But Autosteer replacing the driver steer should avoid this mismatch -- TACC and autosteer should agree on whether to stop behind a stopped/parked car, or plot a path around it and maintain speed.
