I agree, ACC sucks. We have a fleet of 2016 and 2017 Volvo Class 8 trucks. And on the highway they are nothing but a pain in the rear. They slow the tractor-trailer down when approaching another vehicle, and you have no choice but to over-ride the system by pressing the accelerator pedal. They slow the vehicle WAY before you get close enough to set up your pass. So now you are "on the pedal" trying to maintain your speed, buzzers and lights start flashing while you are trying to watch your mirrors for upcoming traffic and find your "hole" to squeeze into the passing lane, and next thing you know you are going above the speed that the highway patrol will start writing. So then you have to fumble with the switch to kill the ACC, check your speedo, watch your distance from the vehicle in front of you, watch for his brake lights, check your mirrors again, flip on your turn signal, and start your pass. If you forget to kill the ACC and get too close the tractor-trailer in front of you, the system will automatically slam on the brakes, just as you are pulling into the passing lane and the radar and computer thinks you are still right behind the truck in front of you, then you get into the passing lane, but are going 10 mph slower than when you started your pass, and all the traffic coming up in the passing lane has to slam on their brakes, because you look like an idiot, and the truck that was going slower than you is now 150 ahead of you.
It's a stupid mess of a system, designed by engineers educated above their intelligence, sitting in a corner office of some high-rise building, trying to devise a system to prevent morons that are too busy texting and driving, from getting into rear end collisions. If your a driver that doesn't mind letting the cars or trucks in front of you dictate your driving, that's fine. If your the moron that can't put your phone away for a few minutes or hours while driving, I guess that's fine too. But when real drivers have places to go, we want full control of the vehicle at all times, not some computer controlling our speed, braking system, and reporting every little thing to a call center in Pakistan, or notifying me of a "hard braking event", I think I would be smart enough to know when I hit the brakes hard, and a very rare event for a good driver.
Set the cruise only when there is little to no traffic, always look WAY ahead of where your going, assume that a vehicle will pop out of every driveway and side street in your path. Check your mirrors and gauges every few seconds, and drive it like you stole it. Let the passengers admire the flowers on the side of the road, and dick around with their phones. These days I trust agressive drivers, they are usually on top of their game. It's the lolly-gagers holding up traffic, driving 5-10 mph under the speed limit that scare me, almost every one I pass is holding their phone in front of their face. I'm not dissing the OP at all, the vehicle came with ACC and I guess it should work properly, but we have disabled the ACC through the ecm in most of our trucks, and will never order another truck with it. It is also unsafe in snow or icy road conditions and can cause the truck to skid/slide without any driver input. I don't know if you can disable ACC in new passenger vehicles, but I would. This post is already proof that they are not fail safe, and having a system, controlled by wires, diodes, resistors, electricity, etc. and a system that controls the brakes, is just too scary for me. Keep the braking system simple and safe, and give me full control even if everything else in the vehicle fails. Know your vehicles limits, and keep a happy following distance, we all know when too close is too close.
Just my professional opinion after 37 years of accident-free, moving violation-free, and over 4 million miles behind the wheel of dozens of 80,000 lb. 53' tractor-trailer sleeper trucks. And oh! I smile when I see a new Camaro hauln-butt and cutting me off on the highway, I know his cruise control is in the off position. Thats when I say to myself "You go Dude"!
