# Collision warning false positives when passing semi-trailer trucks



## cofre_atlas (Jun 20, 2017)

I took my Atlas SE with tech for its first 2+ hour roadtrip this past weekend.

With the adaptive cruise control on and set at about 67mph, I had two false positives with the collision avoidance warning. In both occasions, I was driving in the lane immediately to the left of a semi-trailer truck (passing it), and as I was about halfway done, the 'apply your brakes' warning came on without any reason (I wasn't cut off, no one in the road ahead was braking suddenly or anything similar). Afraid it might brake without my input, I tapped the brake lightly to disable the warning and had to press the accelerator to pick up speed again. I passed both trucks with no issue after the first warning for each.

Has anyone with an Atlas or other VW experienced this?


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## DJMcGoven (Mar 2, 2007)

cofre_atlas said:


> I took my Atlas SE with tech for its first 2+ hour roadtrip this past weekend.
> 
> With the adaptive cruise control on and set at about 67mph, I had two false positives with the collision avoidance warning. In both occasions, I was driving in the lane immediately to the left of a semi-trailer truck (passing it), and as I was about halfway done, the 'apply your brakes' warning came on without any reason (I wasn't cut off, no one in the road ahead was braking suddenly or anything similar). Afraid it might brake without my input, I tapped the brake lightly to disable the warning and had to press the accelerator to pick up speed again. I passed both trucks with no issue after the first warning for each.
> 
> Has anyone with an Atlas or other VW experienced this?


Is the Atlas' system radar based? I wonder if something with the semi's cause interference as you drove past.


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## beastcivic (May 27, 2003)

You may want to ask your dealership to check the adaptive cruise control / avoidance system alignment. I've heard here (in the B7 Passat forum) and in other forums I'm in with vehicles with adaptive cruise / avoidance capability, that alignment can be off and cause false inputs because the system is biased towards the left or right of the car, more so than straight ahead. 

In a few cases the dealership has adjusted alignment of the radar/camera system, and the issues were resolved.


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## vwatlasusa (Feb 26, 2017)

*adaptive cruise control*

I know car techs are lot advanced now compared to few years ago but I am still afraid to use adaptive cruise control - not to scare anyone but what if the car ahead brakes and my vehicle doesn't brake and keep going. It still a hardware/software combo. Being in IT, i know it can go wrong sometimes. I would at least like to have control on braking. I still cant trust adaptive cruise and auto pilot etc..


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## chipster (May 30, 2017)

*Still does not take the place of the driver*



vwatlasusa said:


> I know car techs are lot advanced now compared to few years ago but I am still afraid to use adaptive cruise control - not to scare anyone but what if the car ahead brakes and my vehicle doesn't brake and keep going. It still a hardware/software combo. Being in IT, i know it can go wrong sometimes. I would at least like to have control on braking. I still cant trust adaptive cruise and auto pilot etc..


I don't think the purpose of the adaptive cruise control was to relieve the driver's responsibility of driving. It does help with keeping a certain distance (user-settable) from the car in front of you. I've used this feature several times so far. I hope I don't have to use it for braking all of a sudden. I'm not anxious to try it either 

Is there a safe diagnostic that tests whether the emergency braking feature is operational??? beside throwing a basketball in front of the Atlas ??


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## puma1552 (Jul 6, 2012)

vwatlasusa said:


> I know car techs are lot advanced now compared to few years ago but I am still afraid to use adaptive cruise control - not to scare anyone but what if the car ahead brakes and my vehicle doesn't brake and keep going. It still a hardware/software combo. Being in IT, i know it can go wrong sometimes. I would at least like to have control on braking. I still cant trust adaptive cruise and auto pilot etc..


You mean like in this video?


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## vwatlasusa (Feb 26, 2017)

puma1552 said:


> You mean like in this video?


Haha.. kind of..


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## walksonair (Aug 29, 2017)

just had this happen while on my road trip. I thought it was a fluke at first but the second one was really annoying..scared my passengers a bit because while on ACC the car hot the brake momentarily but kept going anyways. Once there was a white semi that got into my lane and the ACC and the LKS just turned off and said it was unavailable.


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## der_apoteker (Mar 27, 2017)

I have front assist but I don't get any warnings or prompts or slowdown unless acc is engaged. Per vcds the pedestrian monitoring is not active either.


Sent from my SM-G900R4 using Tapatalk


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## Yul-Sav (Aug 6, 2017)

Yesterday I had he front assist braking false positive while cruising at 80 mph passing a big semi... The system sounded an alarm and displayed a red icon in the virtual cockpit and literally SLAMMED on the brakes for me... The wife and I almost had a heart attack.... This thing is flat out dangerous. Anyway to disable this? I'll talk to the dealer about my experience but this is an accident waiting to happen.


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## richyrich999 (Oct 20, 2008)

Remember - these are just assistance technologies - you are still in charge of driving and they may or may not assist with decisions. The general consensus by the people who matter is they are better to have than not, so best get used to it - they reduce crashes and that helps control injuries, and insurance rates!


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## not_so_furious (Mar 21, 2002)

I had a few false alarms on a road trip over the summer. It don't think it ever activated the brakes, but it gave a warning. One time was when a car was entering the highway from the on-ramp. Maybe the system thought there was going to be a collision? The other times all occurred when I was passing semi trucks.



richyrich999 said:


> Remember - these are just assistance technologies - you are still in charge of driving and they may or may not assist with decisions.


If the car decides to slam on the brakes, it's taken that part of the decision making out of your control.

For someone in the passenger seat, it's quite startling because they're probably not paying attention as much as the driver. From the driver's seat, it's not as shocking, but it will still get your blood flowing.


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## Yul-Sav (Aug 6, 2017)

It was the first time this ever happened to me. The car didn't stop completely but went from 80 to 60 in half a second (wasn't normal ACC slow down). The truck was a big black logging truck (bigger than a normal rig). It may have hugged the line a little but wasn't coming in my lane. Not which is worst front collision or getting rear ended because the driver following doesn't brake...


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## juched (Nov 12, 2004)

Reading this thread, I am scared to try ACC now. Wonder if this is a limitation of the system or just a calibration. I was looking forward to this feature.


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## nkresho (Aug 8, 2010)

I love ACC and use it all the time for highway trips. 

That said, the first trip we took I did have one false positive, similar to what was mentioned above. It was a bit less intrusive, but it was a semi in the lane to the right of me. I was passing him. He did not come over the line, but the sensors seem to have thought he did. I got the red dash warning, a beep, and a tap of the brakes, but it was not a full slam or slowdown. I was able to press the gas and accelerate out of it. Only happened the one time during a 500 mile each way round trip. 

Later, during the same roadtrip, the ACC did go offline for a few minutes. It said the sensors were not functioning and that ACC was unavailable.  Icon went gray and the little rearend of the golf in the MFD did not show when there was a car in front of me. Without a restart, a few minutes later it started working again. Hasn't had a single hiccup since, and this all happened in July.


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## GTINC (Jan 28, 2005)

nkresho said:


> I love ACC and use it all the time for highway trips.
> 
> That said, the first trip we took I did have one false positive, similar to what was mentioned above. It was a bit less intrusive, but it was a semi in the lane to the right of me. I was passing him. He did not come over the line, but the sensors seem to have thought he did. I got the red dash warning, a beep, and a tap of the brakes, but it was not a full slam or slowdown. I was able to press the gas and accelerate out of it. Only happened the one time during a 500 mile each way round trip.
> 
> Later, during the same roadtrip, the ACC did go offline for a few minutes. It said the sensors were not functioning and that ACC was unavailable. Icon went gray and the little rearend of the golf in the MFD did not show when there was a car in front of me. Without a restart, a few minutes later it started working again. Hasn't had a single hiccup since, and this all happened in July.


Has it occurred to you that the system can only work properly if the lane lines are very visible and well maintained. VW can't control that.


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## Yul-Sav (Aug 6, 2017)

Had another one on my way back from the road trip I was on. This time I just got the alarm (no braking). It was passing another rig. Both time it appears the rig may have been different size or shape has just usual rigs. This time it was a rig hauling heavy construction equipment (loader). Perhaps this throws the sensors off...


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## walksonair (Aug 29, 2017)

juched said:


> Reading this thread, I am scared to try ACC now. Wonder if this is a limitation of the system or just a calibration. I was looking forward to this feature.


Ah, I bought this car primarily for the ACC...and I've used it non-stop. Especially in school zones where I have to be really cognizant of not exceeding 20MPH. I'm sorry you're having concerns but thought I'd add my experience as another data point. Also, ACC really does reduce the stress of traffic on the highway making my drive way more enjoyable.

BUT, I always am very diligent about monitoring just like when I kick-off the AP at 500ft during a CATIII landing.


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## cofre_atlas (Jun 20, 2017)

*happened again*

Hi guys,

it seems like this is a recurring issue for the Atlas, from all your posts and my experiences. I went on a roadtrip this weekend and this happened again. I was passing an RV to my right, and the 'apply the brakes' message appeared. I can't remember if I had the ACC on at the time, though. I might have switched it off since that part of the road had unclear lane markings.

I wonder if this is a common issue for VW cars or just the Atlas.


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## JohnNS (Sep 21, 2015)

For what it's worth, have had zero false positives or anything out of the ordinary with our Atlas (about 5500kms so far). *knocks on wood*


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