There are several ways to communicate: - turn signal to initiate a turn. - scroll up/down on the right steering wheel control to increase/decrease max speed -

There are several ways to communicate: - turn signal to initiate a turn. - scroll up/down on the right steering wheel control to increase/decrease max speed - left/right on the right steering wheel control to increase/decrease follow distance - nudge the gas pedal to be a little more aggressive (starting from a stop sign, executing a turn that FSD has already started signaling, etc - and sometimes I just take control via brake or stalk. I generally don't disengage with the wheel since that keeps the speed on auto. As for when the loaner didn't stop, it didn't have FSD. So while it looked like my car, it didn't have the same features as my car (just basic autopilot, not FSD). I have not had situations where FSD was engaged and failed to stop or brake from highway speeds.