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Discussion Starter #1
I recently bought a 2017 Honda CR-V with adaptive cruise control.

While I am generally pleased with the car, I started using A.C.C. and I have a problem.

ACC drives well in traffic, including heavy traffic, brakes gently, leaves plenty of following distance and so on. People take advantage of the following distance and cut me off, but I do not care as I am a CDL driver and mostly want to not have accidents. All good, the car slows down, accelerates, stops and resumes. OK.

The problem is that if I go at full speed, and there is a car STOPPED far away, my CR-V will happily speed along and will NOT notice this stopped car and will NOT slow down. A normal good driver would notice, slow down gently, etc, and my car just barrels full speed.

I was, of course, paying full attention during my tests and slammed the brakes, to avoid what looked like an imminent collision, but it was a nerve wracking and disappointing experience.

Has anyone else had this issue?

I do realize that ACC is not a substitute for a fully alert driver and its job is just to ease the work of my feet -- but still it seems wrong and unsafe.

Any comments? Does your ACC slow down for stopped cars ahead?
 

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It will recognize it, but later than you would be comfortable with. The range of the radar is only so far and takes action based on time 2,3,4 or 5 seconds. It will stop but will brake abruptly.

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Great advice!

As you get more proficient with sensing you'll get to a point where you'll want to vary the distance the system looks down the road. It all depends on traffic conditions
 

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If I understand the systems correctly, it's not the ACC that should slow you down and stop you. You have to be locked onto that car ahead, and it has to be the one you're following. It's the collision mitigation braking system - CMBS- that should detect the stopped vehicle and stop you. The CMBS doesn't work on my 2017 CRV, either. I'm going to take it to the dealer this week.
 

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If the acc is engaged it will react to cars as you come upon them. Coming up on a stopped car at speed gives a very short window for when the car is detected and when it needs to apply the brakes. It will work, but you will stop very short. If you are paying attention, you will see the stopped car visually well ahead of the radar.

If you watch the ACC when driving in normal traffic, you can get a good sense of the sensing distance for the radar. You can see cars in the lane ahead of you before the radar locks onto them. It's not super far.

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Discussion Starter #6
Great advice!

As you get more proficient with sensing you'll get to a point where you'll want to vary the distance the system looks down the road. It all depends on traffic conditions
OK, how would I vary that distance? I am sorry, you posted images but I am not allowed to view images due to my low rating on this site.
 

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In ACC, you vary the distance (there are three settings) by pressing the right-side part of the cruise control ring. You will see one, two, or three bars appear behind the image of the car you're locked onto. Each press adds one more bar. The more bars, the further the distance.
 

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The radar isn't long range, it might only see 100 meters out in ideal conditions. As others have said, it takes time for the software to acquire the target with confidence and then decide what to do and that's all happening while the cars are closing-in at a high rate of speed.
 

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Not only is range an issue. we have to understand that what we see out there is not what the radar sees. We see cars, road signs, guard rails, overpasses, ect. All the radar sees are big blobs and little blobs. It's up to the software, with help from the camera to figure out which blobs it needs to react to and which ones to ignore. Tuff job when you think about it and why we can't get too comfortable allowing it to make decisions for us.
 

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Discussion Starter #10
Thank you, ladies and gentlemen.

I think that I agree with you for the most part, ACC is a difficult application and I am thankful to it for what it saves me, which is a lot of foot pedaling and button pressing in traffic. It is not a self driving car and was never advertised as such.

It is not and never was a replacement for a safe and attentive driver and I will always give my driving the utmost attention.

i
 

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Unless I'm mistaken, Honda Sensing ACC is NOT designed to detect stopped vehicles unless they were previously detected (while moving) and then come to a full stop. It is impossible for the radar to detect a stopped vehicle - it bounces back the same frequency as any static object in front of the car. The camera and brains of the Honda Sensing system would have to be responsible for detecting a stopped vehicle solely on their own, and I don't think the hardware and software in these vehicles is safely capable of it yet.

To those who say it will stop at the last second, I highly recommend you never rely on that. I'm surprised it would stop at all for an undetected stopped vehicle. I know all the FCA vehicles I had with ACC would absolutely slam into the back of any stopped vehicle if it weren't previously locked onto it. The systems are not designed for that kind of driving yet.

It's CRUISE CONTROL. Not autonomous driving.
 

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You are splitting hairs between when ACC turns into CMBS.

It will hit the brakes before collision. If you don't believe, try setting up a cranked box wrapped in tinfoil on your street and approach it with ACC engaged.

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Discussion Starter #13
I personally experimented with approaching stopped vehicles with cruise control.

It allowed me to approach the stopped vehicle, without slowing down, so closely that it was clearly scary and totally unadvisable.

I still stopped, of course, but clearly this is the sort of thing that I would never want to try for real even for one more time.

I would think that even CMBS should be more sensitive and not allow me to do what I attempted.

i
 

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Get the big owners manual from Honda, or read the one on the CD. Check the CMBS system description from page 516 to page 527. In the first part of that section, it tells you what the CMBS WILL do. Then in the last part, it tells you what it WON'T do. In the first part for example, it says it will detect a pedestrian crossing in front of you. At the end of that section, it tells you that the pedestrian must not be running, must not have his hands raised, must not be carrying anything like a suitcase or a bag of groceries, must be completely alone, and must be taller than 3 feet and shorter than 7 feet. In other words it cannot be a child or a professional basketball player. If you read the entire section you will find that there are so many exceptions, that this system is all but useless on this car. On my car, system doesn't work in anyway or fashion. It doesn't detect anything. It does not work.
 

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slybarman - I went to the dealer before I posted (about my CMBS/FCW not working) - this is what they showed me in the manual as the reason it doesn't work. The ACC, however, DOES work as advertised.
 

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slybarman - I went to the dealer before I posted (about my CMBS/FCW not working) - this is what they showed me in the manual as the reason it doesn't work. The ACC, however, DOES work as advertised.
If it doesn't detect ANYTHING as you say, the dealer is full of crap and you should tell them as much.

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I recently bought a 2017 Honda CR-V with adaptive cruise control.

While I am generally pleased with the car, I started using A.C.C. and I have a problem.

ACC drives well in traffic, including heavy traffic, brakes gently, leaves plenty of following distance and so on. People take advantage of the following distance and cut me off, but I do not care as I am a CDL driver and mostly want to not have accidents. All good, the car slows down, accelerates, stops and resumes. OK.

The problem is that if I go at full speed, and there is a car STOPPED far away, my CR-V will happily speed along and will NOT notice this stopped car and will NOT slow down. A normal good driver would notice, slow down gently, etc, and my car just barrels full speed.

I was, of course, paying full attention during my tests and slammed the brakes, to avoid what looked like an imminent collision, but it was a nerve wracking and disappointing experience.

Has anyone else had this issue?

I do realize that ACC is not a substitute for a fully alert driver and its job is just to ease the work of my feet -- but still it seems wrong and unsafe.

Any comments? Does your ACC slow down for stopped cars ahead?
I have a 2016 Crysler loaded with front and back sensors to include radar and optical. The ACC works perfectly (as do the front and rear cross path detection with auto braking etc) EXCEPT with stationary vehicles. I don't think it has anything to do with computer reaction time since the failure occurs at slow speeds (30/40 MPH) as well as faster. If a vehicle is at a stop light ahead, for example, and is slightly moving the ACC detects it and stops appropriately. However if the vehicle is completely stationary, NOTHING! I've spoke with Chrysler Corp on numerous occasions and have even had two dealer shops check it out. (They refused to take it for a test drive duplicating my issue due to "possible danger" to their mechanics!!) Their last suggestion was to take a video of the failure of the ACC to recognize a stationary vehicle. Seriously? Try doing that on your own. I've also read articles that related the same problem from other auto brands. A Tesla owner was even involved in a fatal accident due to a "suspected" ACC failure to recognize a stopped vehicle.
At this point I think it's an industry wide issue that's sufficiently seldom encountered to warrant investment in a solution that could lead to a VERY extensive and expensive recall.
 
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