I was showing a friend TACC and how it works/performs over the weekend and during a mundane red light stop, the TACC failed to brake properly and we almost ended up rear ending the car in front of us. Needless to say, she was less than impressed. I have a dash cam and recorded it here: P85D TACC fails to brake at red light. Almost accident. - YouTube It's hard to tell but we were going at a decent but manageable speed and was following the blue Prius in front of us. The TACC was on and i did not manually step on the brakes at all, even until the end. Had I not swerved to the right, we would have rear ended the car. It appears that at that situation, TACC might have thought the road curved to the right given that the vehicle in front of me started going towards the right and also the lane opens up as well. It did not take notice on all the vehicles that have stopped and also the vehicle in front of us that has been stopped. So guys, be careful using TACC, especially if the car in front of you is leaving the lane. It seems that TACC does not track or does not like to track anything beyond the vehicle in front of you.