First and foremost, I want to say that the misses, the dog and I are safe, but yesterday’s harrowing experience was an eye opener. Will traveling south on the 405 highway in moderate to medium traffic, and I encouraged the misses, who was driving, to use ACC. For about twenty miles, the system, set at 75 mph, worked great, even bringing the car to a complete stop several times as traffic increased. Unfortunately, while stopped, the car in front of us exitted the carpool lane, and the misses steered the car slightly to the left to maneuver around the car. Suddenly, the car bolted forward as if it did not see the white BMW in front. Due to her quick reaction time, the misses stopped our Macan car before slamming into the car in front, and luckily the car behind us was not too close. Shaken and confused, the misses has vowed never to use ACC again. I am, however, open to using this technology. I will let the Porsche know of our experience, and I will be interested in their response, if any. Once we arrived at our destination, the misses did a little research and found out that other adaptive cruise control systems by other car makers other have struggled in similar scenarios. We provide this information to the forum as a note of concern when using ACC.