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Discussion Starter · #1 ·
My ascent hasn't been in any accidents so the whole getting rear ended hasn't happened to me. I did notice something I thought was extremely peculiar and could be cause of some accidents. Today while traveling on the interstate with a moderate amount of traffic and ACC engaged, I noticed that the Ascent would rapidly decelerate without appearing to actually be braking when vehicle in front slowed down immediately. While I can't be certain whether it was using the brakes to slow down, I can confirm that the time between when the rapid slowing began and when the brake lights appeared to show up on the display between the speedo and tach was longer than 2-3 seconds. I always drive with my foot covering the pedals in case I feel the need to take over from the driver assist systems, and usually am not watching the representation of my vehicle on the screen, but it caught my eye when it happened today. After watching out for it on the remainder of our trip I definitely noticed it happening a few other times, and was wondering if anyone else had noticed something similar. I've seen at least 3 postings of people getting rear ended in their new Ascents either on here on or Facebook, and would love to know if they were using ACC at the time of their fender benders.
 

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I have wondered about the same thing when I engine brake and hold gears in traffic.

I don't have your systems, but the concept is the same. No brake lights, means other drivers can't adjust as quickly.

But other active system sure can. Right? The adaptive systems favor other adapter systems. In less years than we can all imagine, the real driver will be the anomaly that the systems work around. I have started to left foot brake, even though I am engine/gear braking ... or tap it, to alert the driver behind I am slowing down. Keyword Driver.
 

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I doubt the acc and engine braking caused any accidents unless you guys are using the acc and following at the minimum level. Everyone engine brakes every time they take their foot off the gas and people are piling up every minute of every day.
 

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My ascent hasn't been in any accidents so the whole getting rear ended hasn't happened to me. I did notice something I thought was extremely peculiar and could be cause of some accidents. Today while traveling on the interstate with a moderate amount of traffic and ACC engaged, I noticed that the Ascent would rapidly decelerate without appearing to actually be braking when vehicle in front slowed down immediately. While I can't be certain whether it was using the brakes to slow down, I can confirm that the time between when the rapid slowing began and when the brake lights appeared to show up on the display between the speedo and tach was longer than 2-3 seconds. I always drive with my foot covering the pedals in case I feel the need to take over from the driver assist systems, and usually am not watching the representation of my vehicle on the screen, but it caught my eye when it happened today. After watching out for it on the remainder of our trip I definitely noticed it happening a few other times, and was wondering if anyone else had noticed something similar. I've seen at least 3 postings of people getting rear ended in their new Ascents either on here on or Facebook, and would love to know if they were using ACC at the time of their fender benders.

I have a feeling that the display is not coordinated with the actual lights in the rear. The lights in the rear should be directly linked to the physical brakes, so the ACC activating them vs human activation should have no bearing.
 

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I usually engine brake or try to hypermile. Part of my commute is through a city so I don’t really make a lot of friends when I coast from the posted speed limit of say, 35 down to 10 and roll towards the red light rather than doing the whole gun it and slam on your brakes last second thing.

Everyone’s absolutely right. It depends on the driver. A bad driver is only going to be “enabled” by the anti collision systems to continue being a bad driver. A good driver will continue to be a good driver - and anticipate things rather than react to them.

But engine braking will only do so much. While you feel the sudden change in acceleration or constant speed to a deceleration, it won’t be drastic enough to come to an abrupt stop without the brakes. Unless the person behind you is kissing your bumper they should have time to react. And if they don’t, that’s really never your fault.

We had an article in the paper the other day about someone that rear ended someone with no working brake lights and they still were at fault. The other driver was citationed for failure to maintain functional stop lights but the cause of the crash was still the car from behind.
 

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Discussion Starter · #6 ·
I have wondered about the same thing when I engine brake and hold gears in traffic.

I don't have your systems, but the concept is the same. No brake lights, means other drivers can't adjust as quickly.

But other active system sure can. Right? The adaptive systems favor other adapter systems. In less years than we can all imagine, the real driver will be the anomaly that the systems work around. I have started to left foot brake, even though I am engine/gear braking ... or tap it, to alert the driver behind I am slowing down. Keyword Driver.
This was exactly my thoughts, the system is working as it is intended but I think only with other adaptive systems in mind. I was following at more than 4 car lengths at a speed of around 55-60 according to how I set the system, but when the car begins to decelerate quickly I can't imagine that another driver following me can recognize the abrupt change in speed without being able to react to the brake lights on my vehicle. This is especially true when the car is substantially smaller than the Ascent and the driver can't see the brake lights from the cars in front of me either.
 

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I have a feeling that the display is not coordinated with the actual lights in the rear. The lights in the rear should be directly linked to the physical brakes, so the ACC activating them vs human activation should have no bearing.
This is definitely false. When the ACC engages the brakes the brake lights illuminate just as they should. You can even see it on your cluster.
 

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This is definitely false. When the ACC engages the brakes the brake lights illuminate just as they should. You can even see it on your cluster.

You misinterpreted my post. I'm in agreement with you. The OP is stating that the brake lights do not illuminate in the cluster visual immediately. There is a delay per the OP.
 
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I doubt the acc and engine braking caused any accidents unless you guys are using the acc and following at the minimum level. Everyone engine brakes every time they take their foot off the gas and people are piling up every minute of every day.
I was speaking more to things like dropping 1 to 2 gears, or holding 2nd gear down a hill, if am I am slowing too much, then bump into 3rd ... the back to second. In most situations, the car in front of me is accelerating, then braking, then rolling, then braking. The car behind me see no brake lights from my car unless I were to fake-foot it.
 

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I was speaking more to things like dropping 1 to 2 gears, or holding 2nd gear down a hill, if am I am slowing too much, then bump into 3rd ... the back to second. In most situations, the car in front of me is accelerating, then braking, then rolling, then braking. The car behind me see no brake lights from my car unless I were to fake-foot it.
I get ya. I still would argue if you can't see/notice a difference in speed between you and the car in front you then maybe you should rethink driving, brake lights or not.
 

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I get ya. I still would argue if you can't see/notice a difference in speed between you and the car in front you then maybe you should rethink driving, brake lights or not.

Agree... when I go down a hill, I used reduced gear to slow down while everyone else slams the brakes. I've never been rear-ended in that situation even though my break lights were not activated while slowing down via reduced gear.
 

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I have a feeling that the display is not coordinated with the actual lights in the rear. The lights in the rear should be directly linked to the physical brakes, so the ACC activating them vs human activation should have no bearing.
This is definitely false. When the ACC engages the brakes the brake lights illuminate just as they should. You can even see it on your cluster.
The display is delayed by a little bit. You can test this by actually manually applying the brake pedal and watching either display (the brake lights on the dash display and the ones on the ACC display will light up).

The Ascent makes massive use of CVT and engine braking, and can actually maintain speed or slow down speed on pretty steep inclines with no brake use at all. I've literally even slowed down the car using ACC via exclusively engine/CVT braking while going down the mountains into Ticonderoga, NY (Rt 73, for those familiar) where normally my other cars would be smoking the brakes by the bottom to do the same thing.

With that said, the Ascent makes decent use of CVT and engine braking for ACC operation. I've already submitted a suggestion that SoA updates the software to activate the brake lights during heavy CVT&engine braking during ACC operation.

Figuring out how much of it is the display's slight delay and how much of it is the car actually not using the brakes is an interesting task that would likely require a couple of coordinated cameras or someone following?
 

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Discussion Starter · #13 ·
The display is delayed by a little bit. You can test this by actually manually applying the brake pedal and watching either display (the brake lights on the dash display and the ones on the ACC display will light up).

The Ascent makes massive use of CVT and engine braking, and can actually maintain speed or slow down speed on pretty steep inclines with no brake use at all. I've literally even slowed down the car using ACC via exclusively engine/CVT braking while going down the mountains into Ticonderoga, NY (Rt 73, for those familiar) where normally my other cars would be smoking the brakes by the bottom to do the same thing.

With that said, the Ascent makes decent use of CVT and engine braking for ACC operation. I've already submitted a suggestion that SoA updates the software to activate the brake lights during heavy CVT&engine braking during ACC operation.

Figuring out how much of it is the display's slight delay and how much of it is the car actually not using the brakes is an interesting task that would likely require a couple of coordinated cameras or someone following?
This is why I brought it up, and am glad that I'm not the only that thinks this is something that the engineers may want to look at.
 

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We use ACC on our Outback and Legacy to maintain speed/driving distance while descending our Colorado Front Range canyons. It does a great job of throttling down and will apply brakes when appropriate. I never use the paddle shifters now that I've seen how ACC does a superior job. I get the lack of brake lights at times to the rear but I love that the system does not automatically ride the brakes while descending the canyons.
 
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