Jerky cruise control

carsrmilife

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Brighton, MI
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Regal TourX
Does anybody with ACC experience abrupt braking when the car slows to traffic ahead? Out of the past few vehicles I've had with ACC, this one is quite jerky. Instead of coasting when it senses traffic ahead, it seems like it waits until it reaches the gap threshold and then gives the brakes a good tap. It works great for maintaining a steady following gap, to fend off people cutting you off, but isn't so great otherwise.
 

Lt0302

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Regal Sportsback GS
Does anybody with ACC experience abrupt braking when the car slows to traffic ahead? Out of the past few vehicles I've had with ACC, this one is quite jerky. Instead of coasting when it senses traffic ahead, it seems like it waits until it reaches the gap threshold and then gives the brakes a good tap. It works great for maintaining a steady following gap, to fend off people cutting you off, but isn't so great otherwise.
mine is the same way! ........especially aggressive braking when someone pulls in front of you, a human would let of the gas and then brake gently.......had a few people almost rear end me because of the aggressive braking
 

Hinky

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Regal Tourx
I've actually been very pleased with how smoothly it approaches slower vehicles. However, mine often doesn't realize when the person ahead of me has moved into a turn lane. It'll slow down along with them and I have to take over.

Also, I wish the following distance could be increased much further between 30 and 60MPH. It follows more closely than I would on my local roads even on "far" gap.
 

JoeBlog

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Wichita
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1967 Wildcat Convertible, 2019 Regal TourX Essence
I’ve noticed my car brakes rather enthusiastically while ACC is being used. I figure that the algorithm is set to be more cautious than the driver. It also brakes “flatter” than a human would; the rear brakes seem to be doing more work, as the car doesn’t nose down like it does when I have to brake suddenly.
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carsrmilife

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Brighton, MI
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Yea if I am coming up to traffic from a distance, it seems to brake normally. But in normal traffic, with merging and speed variance, that’s when it gets choppy. It’s definitely an area that the Outback excels in.
 

justiz00

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Tourx
If I suspect the vehicle in front of me will enter the approach boundary, I hit cancel and coast in on them, then hit resume once the gap opens or once the speed has stabilized and we maintain that following distance. Otherwise, I will press the gas pedal and watch for the CC indicator to turn back to green before releasing.
 

FavaBean

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DE
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2018 Regal TourX Essence
I've always wondered how mad the people behind me are getting when the ACC jams on the brakes in traffic. It's also is very jerky when traveling on a significant downgrade and the car is trying to maintain the set speed.
 

saab93driver

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2019 TourX
the TourX seems to be about the same as the system on my Subaru which was pretty smooth most of the time. Occasionally I thought it (and the Buick) are late to react then apply a lot of brake suddenly.
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Foxbat

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Michiana
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2018 Quicksilver Regal Sportback Essence AWD
At least the brakes and CHMSL come on when the ACC slows the car. Imagine how bad it would be if GM hadn't added that to the programing, lots of Regals getting rear-ended because people weren't expecting the brake-check.
 

carsrmilife

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Brighton, MI
Buick Ownership
Regal TourX
the TourX seems to be about the same as the system on my Subaru which was pretty smooth most of the time. Occasionally I thought it (and the Buick) are late to react then apply a lot of brake suddenly.

The Outback does brake kinda late in the game, but it is leaps and bounds better at just coasting and backing off when a car merges in, but is accelerating. The TX just flat out mashes the brakes for a half second to get back to its gap threshold. In the grand scheme of things, I do feel less on edge in the TX, with the rigid gap maintenance, as there have been many times I thought the Outback wasn't going to stop, it's just not great to live with sometimes.

At least the brakes and CHMSL come on when the ACC slows the car. Imagine how bad it would be if GM hadn't added that to the programing, lots of Regals getting rear-ended because people weren't expecting the brake-check.
It took me a second to toggle through all of the Marine Corps, IT, and automotive acronyms for that one. Haven't seen CHMSL used in some time. Anywho, I would imagine there would be accidents a plenty and all of us would be driving something else, since there are no parts available to do repairs.
 

Foxbat

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Michiana
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2018 Quicksilver Regal Sportback Essence AWD
It took me a second to toggle through all of the Marine Corps, IT, and automotive acronyms for that one. Haven't seen CHMSL used in some time. Anywho, I would imagine there would be accidents a plenty and all of us would be driving something else, since there are no parts available to do repairs.
Sorry; I'm in IT, so it's an occupational hazard… ;)
 

SweetWafer

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2018 Regal TourX
it seems like it waits until it reaches the gap threshold and then gives the brakes a good tap
In most traffic it's fine, but if there's more than a 5mph difference in speed the car does act rather surprised when the vehicle in front reaches the gap threshold, even though it has "seen" the car (green icon) for much longer than that. I usually help it out a bit by preemptively lowering the set speed, which sort of defeats the purpose of ACC. On the other hand I'm still supposed to be driving the car, so I guess these little adjustments are to be expected. I assume GM wants us to upgrade to Cadillacs to get a system that considers speed differentials outside of the gap zone.
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carsrmilife

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Brighton, MI
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Sorry; I'm in IT, so it's an occupational hazard… ;)
No worries, as am I!

In most traffic it's fine, but if there's more than a 5mph difference in speed the car does act rather surprised when the vehicle in front reaches the gap threshold, even though it has "seen" the car (green icon) for much longer than that. I usually help it out a bit by preemptively lowering the set speed, which sort of defeats the purpose of ACC. On the other hand I'm still supposed to be driving the car, so I guess these little adjustments are to be expected. I assume GM wants us to upgrade to Cadillacs to get a system that considers speed differentials outside of the gap zone.
Once that system trickles down, you will likely be correct! They should study Honda's "safety system", it has been my favorite out of the ones I have had.
 

garbageguy

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Regal TourX 2019
Does anybody with ACC experience abrupt braking when the car slows to traffic ahead? Out of the past few vehicles I've had with ACC, this one is quite jerky. Instead of coasting when it senses traffic ahead, it seems like it waits until it reaches the gap threshold and then gives the brakes a good tap. It works great for maintaining a steady following gap, to fend off people cutting you off, but isn't so great otherwise.
Sometimes, but I'm learning its tendencies and adjust my control of the car's features accordingly. This is the first Adaptive Cruise Control I've had - I didn't think I'd like it, but I'm getting very used to it, and like it quite a bit. It seems we're heading down the slope to vehicles that operate themselves - I don't like that on its face, but do enjoy the relative ease of operating a newer vehicle (uh-oh, I'm going down that slope)
 

carsrmilife

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Brighton, MI
Buick Ownership
Regal TourX
It sounds like quite a few are preemptively adjusting the settings of the ACC, to avoid the otherwise annoying tendencies. But.... that kinda defeats the purpose of it. By needing to adjust the speed or momentarily shut it off, you're essentially using normal cruise control. A good work around for those of us that are stuck with what we have I suppose, but still annoying that cars that are older have superior systems. If I had to guess, there was likely some code tweaking in the way it operates, to adhere to US laws/standards, resulting in a half baked (rebaked?)/tested system.
 

garbageguy

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Regal TourX 2019
In my opinion, the ACC in this TourX makes this car more comfortable (easier?) to drive than older cars I've driven with "normal" cruise control. No, it's not perfect, but is improving - I don't feel stuck with it. The most annoying thing, for me, is me not paying enough attention when I'm cruising along, and it slows the car's speed because the vehicle in front of me is cruising at a slower speed. I do agree with the OP that the abrupt braking can be annoying, possibly even a safety consideration. I expect many of the driver-assist features to improve - fortunately, I don't think I'll be on this planet long enough that I have to just let a vehicle take me places. When a transporter (yep, Star Trek) is working right, all this vehicle stuff may go away anyway
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