This is a known issue and can occur at times.
I use the ACC quite a lot and as you say the first time you allow your car to charge up to the queue of parked cars under ACC and wait for it to brake takes some courage. ACC often has a higher threshold than the brain and definitely not the forward vision of human eye.
In regard to false positive detections these can occur and are detailed as a cautionary note in the manual for the P7 at least. False detections on a bend for stationary items or oncoming traffic, or in tunnels, weird ones that just trigger seemingly out of nowhere. Also the emergency brake alerts that sometimes trigger.
Of less concern are the side assist alarms that trigger from trees or road signs as you drive past alone on the road.
And finally there is the random ACC disconnect/not available error which requires an ignition off/on to resolve

 

Appreciate that I am coming from a minority position but I cannot ever see myself allowing artificial intelligence and digital interfaces take the responsibility for car control. You make the point that it takes a fair bit of courage to allow the system to take control, agreed, and then to list the possible failures modes makes me think that very few people would have the reaction time and skills to avoid some sort of accident in the event of a last second failure. I think I'll leave the Jetsons to TV.

 

I think I'll leave the Jetsons to TV.

Certainly, understand that feeling, there are sensitivity settings in the vehicle setup which I haven't played with other than the follow distance, for most the standard braking profile is too late and aggressive. (This technology is also not sympathetic to hyper milers either) But if you think back to your first experiences with standard cruise control and that feeling as you crest a hill or enter a bend, many when driving manually will ease off the throttle near the crest/corner (just makes sense). The cruise control holds the throttle all the way giving the sensation of acceleration.
(Physics I think says that you have a constant instantaneous velocity, but the change of direction means that you are indeed accelerating?)
In reality I prefer to brake gently myself as it is more comfortable for myself and passengers, but in the freeway crawl the assistance can be good, until you realize that the standard follow distance leaves enough room for other aggressive drivers to squeeze in front causing the inevitable slow down.

There are occasionally the scenarios where the vehicle decides that it cannot brake quickly enough and will scream at you warning "Depress Brake Pedel"

 

Long story short, I was faced with a 2-3 start stop hour trip down the M1 to the Gold Coast yesterday for a family emergency. Saturday mornings are usually bad on the M1 and school holidays is worse.

So I thought I'd give travel assist a go. It works although it takes some courage to allow the car to brake itself to a stop!

Coming back in the arvo the traffic was relatively light. ACC and TA on at 114k/h. I'm in the 3rd of 4 lanes with no car in front or to the sides, the car suddenly decelerated. Say 114 to 70 in a few seconds. Luckily no one was behind me. I jumped on the throttle and got up to speed again but say 20 seconds later it did the same thing. No warnings or alarms. From then on it worked fine.

Any ideas folks?

Cheers.

Is this 7P model you are referring to?
Irrespectively, haven't had any such issues with the CR, tech is getting quite good, not perfect of course.
With 7P I had for 6 yrs, I didn't have this, such issues either, bought it brand new and sold 6yrs later.

 

MY22 CR

 

It will also decelerate if a car is in your right side lane because it doesn’t want you to pass on the left. Particuarly sensitive if that vehicle is slowing to turn right

 

Yes, I've only recently realised what was going on with passing left. I started a thread on the issue a few weeks back. Not the case in this instance.

 

Coding can change that so it overtakes.
Really strange that you gave these issues, with all the acc and traffic assist driving I haven't faced such

 

You can also set the "aggressiveness" of the ACC acceleration and braking via the setup menu and the control distance via the top switch on the ACC setting arm. Even on the most relaxed settings I still find the braking to aggressive when coming up to stopped cars in your lane but I guess that is a personal preference. So worth playing with those settings if you have not done so.

My biggest personal beef and some thing not easily solved is the emergency braking when a car turns out of the lane into a side street and its velocity is read by the ACC to go instantly down to zero as the ACC picks up the side of the car versus the rear. My biggest concern with this is the car behind me running up the back of my Treg when it brakes needlessly but its hard to program the computer to recognise that situation

I drove 1000kms over the weekend to go skiing at Mt Hotham from Melbourne and did almost the whole trip up and back on ACC without having to touch the brake or accelerator which makes for a relaxed trip. Even going though towns I could leave it set on 100 or 110km/hr and the ACC would slow it down to the speed limit or less due to the traffic I was following. The ACC leaves a safe distance to the car in front and you find you need to be relaxed about cars on the freeway cutting in between you and the car your following in typical aggressive Australian driving fashion and the car automatically slowing down to maintain a safe distance again with the cutting in car.

cheers
Rohan

 

I drove 1000kms over the weekend to go skiing at Mt Hotham from Melbourne and did almost the whole trip up and back on ACC without having to touch the brake or accelerator which makes for a relaxed trip.

A couple of weeks ago I rented a little Audi A3 35 TDI sedan in Germany and was really impressed with the ACC operation on the Autobahn.
Good following distance at all speeds and very reactive. It works so well when set on 200 km/hr however when the lane assist intervenes you **** yourself. (Especially going v max 230+)

The experience reminded me on how good the ACC stalk was on the 7P and the stupid move to make them steering wheel buttons on the CR.

 

That aggressiveness in braking and behaviour when car in front is turning has been vault improved in the cr.
Having the radar higher up helps too I think

 

I’ve got 2021 CP version and use ACC most of the time. I find it fantastic in heavy stop start traffic but use the brake when I see stopped traffic in the distance to avoid the sudden aggressive braking. If road is twisty I set it at a slower speed and use accelerator to go faster on the straight bits. Occasionally there is a false brake alert but very rare so not an issue for me.as I like the security of the automatic accident avoidance if my attention wanders.

 

I use the ACC nearly all the time. It's nice to set the distance and then let the computer slow the Treg down to the speed of the car in front.

I also brake early if I see that the traffic has stopped in front of me. It saves fuel and prevents that emergency stopping effect.

I don't worry about the ACC braking and affecting morons tailgating me. According to the traffic rules they're supposed to leave enough room between cars to safely avoid a collision. Many drivers seem to ignore that rule.