WARNING: crash risk ACC radar cruise control

[fatjoez]

Noticed in MK2 Tiguan but probably same for all ACC radar cruise Vw

Summary:
When changing lane from one with car in front to empty, ACC accelerates the car dangerously fast and does not detect car 50metres ahead stopped in lane.

Driver must force the brakes and disengage ACC to avoid crash.


Example:
ACC radar cruise control on
Highway driving approx 80km/h
Exit highway which has multilanes at exit
Car in front slows down
ACC detects and slows down

Driver (you) change to a lane which is clear for another 50metres before car stopped at traffic light

ACC sees clear lane & accelerates aggressively to reach set speed.

ACC does not respond to stopped car just 50metres ahead and keeps driving at set speed.

Driver forced to manually break when 15-20metres away to avoid crash.


I have now confirmed this behaviour about 10 times in different situations.

The pattern is the same every time.
When car is slowed down from set ACC speed, changing to lane which is clear but has slow or stopped car further ahead - ACC no longer detects or responds to 2nd car and will crash without driver.

This is extremely strange.
Definitely software error.

Has anyone else seen this?
Is there a software update?

Edit: exact same problem experienced by other drivers here
https://www.tiguanforums.co.uk/threads/possible-major-acc-bug.2546/

[99GTT]

I was always under the impression that ACC does not “see” cars that aren’t moving (stopped), unless they are moving to begin with and slow down to a complete stop, eg: following a car off the freeway and stopping at traffic lights.


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[Timmy35851]

Take it to the dealer with video footage

[Suncoaster]

I think that if you read the owner's manual, you will see that the system does not detect stopped cars. I don't think that it's a fault. It may well be an unwelcome characteristic that you have to note. Cheers-John

[Guest001]

Mine doesnt do it and I use it on the highway all the time. Is NOT a Fault It cant see stopped vehicles and thats your job to control it. Same if you drive it up to a wall. It wont see it. Also it doesnt accelerate "dangerously " fast. I have a 162 and it just gets up and goes to get back to set speed which I dont find dangerous.

Try it with a big cardboard box if you dont believe me. Get out on a country road (Plenty in NZ) and stick a big box in the middle of the road. Get up to acc speed and get close to it. Car wont do anything but keep on going. Was exactly the same in my Mk7 Passat.

Also if cornering it can lose sight of the vehicle in front and once again wake up and control it. Tells you things like that in the book in the cellophane in the glovebox.

[Nauend]

i did a quick google and found this behaviour - ACC not recognising a parked vehicle - is know behaviour across a number of car makers/the current technology.

This link discusses some testing done and mentions a few models that will hit the parked car each time:

New cars can stay in their lane—but might not stop for parked cars | Ars Technica (https://arstechnica.com/cars/2020/08/new-cars-can-stay-in-their-lane-but-might-not-stop-for-parked-cars/)

“New cars can stay in their lane—but might not stop for parked cars.”

Was not a limitation I was conscious of (may have read it in the manual ages ago), so its good to know. Lane keep and city autonomous braking are also not perfect from my experience!

[Umai Naa!!]

At the end of the day, you still need to be in control of the vehicle and be aware of danger.

These are driver assist features, they're not meant to be auto-pilot.

[fatjoez]

Thanks everyone for replies.
I read the manual and see it is expected behaviour but it's not a good one.

I shared it to raise awareness because in my personal experience the acceleration after changing lanes and time to brake before crash was only about 5 seconds which is not a lot of time and especially if a driver misjudges and thinks the cruise radar may just be delayed it can be too late and crash.

It's very unusual that given this is literally radar , not camera, that this couldn't have been programmed to detect stopped cars.

[Guest001]

Thanks everyone for replies.
I read the manual and see it is expected behaviour but it's not a good one.

I shared it to raise awareness because in my personal experience the acceleration after changing lanes and time to brake before crash was only about 5 seconds which is not a lot of time and especially if a driver misjudges and thinks the cruise radar may just be delayed it can be too late and crash.

It's very unusual that given this is literally radar , not camera, that this couldn't have been programmed to detect stopped cars.


It is expected when you get a new car you familiarize yourself with it by reading the manual if you arent aware what the various systems do.
Everything has limitations and as you have found when you do a sneaky late lane change to gain a few car lengths advantage it doesnt see the stopped car.
You as the driver are supposed to be in control and have no excuse for running up someones backside and saying " it was on ACC and didnt stop".
Seems as no one else has brought it up on here its not a problem to other owners who have made themselves aware of what the car can and cannot do.
More like owner ignorance than a car fault.

When I got my Tig I sat down and read the relevant parts of the manual before trying stuff. Like how to set drivers seat, how the Nav works, how ACC works. Also have a new Skoda and did the same as even though from the same stable, things are set up quite differently.

Also you dont have to disengage it to stop as it will disengage if you brake and you have to reset it again but a prudent person would before exiting the freeway as you wont be doing that speed on minor roads, so why keep it on and set to over the local speed limit.

Scenario Driver following car off freeway with ACC engaged at 90kph??and is at following speed of car in front Suddenly sees lane beside has only one car in it so whips across and car then tries to get up to set speed (as it should). Car in lane is stopped so driver just rolls on with ACC ( Oh s**t its not going to stop) Of course it wont. Why not disengage it or dab the brakes a bit as you whip across and it would have slowed down naturally. You would have to reengage it after you braked anyway.

Poor driving habits me thinks.

[Flipper Dog]

I have the same issue with my mobile phone, when I am walking along the road taking a selfie, the front camera does not warn me that there is something in my way which results in me walking into it.

Should I complain about this on social media or am I just a fool awaiting a Darwin placement.

[99GTT]

Lol, give him a break [emoji1787]
Having tested it out 10 times in different situations I’m sure he’s in full control, I think he just found it weird that a radar doesn’t detect stopped cars, and he found it strange that It would accelerate instead of keeping distance from the car in front


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[Guest001]

I have the same issue with my mobile phone, when I am walking along the road taking a selfie, the front camera does not warn me that there is something in my way which results in me walking into it.

Should I complain about this on social media or am I just a fool awaiting a Darwin placement.

A very good analogy Flipper and the sad part is they live amongst us and breed

[Guest001]

Lol, give him a break [emoji1787]
Having tested it out 10 times in different situations I’m sure he’s in full control, I think he just found it weird that a radar doesn’t detect stopped cars, and he found it strange that It would accelerate instead of keeping distance from the car in front


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Of course it would accelerate, its supposed to to get up to the speed set for far too high in the circumstance. If the car was moving it would have slowed to keep the set distance.

Im sure he NOT in full control if he nearly ran up the back of the stopped car.

Perhaps read the manual BEFORE driving the car. Oh yeah who does that . Get in the crap and blame the car for own inadequacy.

[anonymousmoose]

Thanks everyone for replies.
I read the manual and see it is expected behaviour but it's not a good one.

I shared it to raise awareness because in my personal experience the acceleration after changing lanes and time to brake before crash was only about 5 seconds which is not a lot of time and especially if a driver misjudges and thinks the cruise radar may just be delayed it can be too late and crash.

It's very unusual that given this is literally radar , not camera, that this couldn't have been programmed to detect stopped cars.

That's a concerning comment. ITS NOT MEANT TO STOP THE CAR in your OPs situation! It's cruise control, not an autopilot. The collision system is designed to assist avoid a crash, but it kick in late only as a emergency. I bet it would have done this but it's not something anyone should be testing and at that speed, it's still likely to crash.

"thinks the cruise radar may just be delayed it can be too late and crash." Then the driver is a moron and should not be driving. Sorry to be harsh but it's true.

It's working exactly as intended. And it works very well.

I find it quite alarming that people would think the ACC is designed avoid a crash. Flip it's similar to the Tesla driver I saw literally reading a book, face down, on the freeway.

[Guest001]

That's a concerning comment. ITS NOT MEANT TO STOP CAR! It's cruise control, not an autopilot. The collision system is designed to assist avoid a crash, but it kick in late only as a emergency. I bet it would have done this but it's not something anyone should be testing and at that speed, it's still likely to crash.

"thinks the cruise radar may just be delayed it can be too late and crash." Then the driver is a moron and should not be driving. Sorry to be harsh but it's true.

It's working exactly as intended. And it works very well.

I find it quite alarming that people would think the ACC is designed avoid a crash. Flip it's similar to the Tesla driver I saw literally reading a book, face down, on the freeway.

As it cant see STATIONARY objects it probably wont stop. Yes maybe eventually they will get it to see them but not in current models.

[anonymousmoose]

As it cant see STATIONARY objects it probably wont stop. Yes maybe eventually they will get it to see them but not in current models.

It's worrisome that people driving cars are not aware of how the technology works.

I remember a UK article with some older people having a go at the Tiguan because the bushes around their roads are were being picked up as objects by the collisions avoidance system and activated the brakes. The lady got so worried she stopped driving the car and the local news wrote an article.

It's happened to me before on a very narrow road, around vineyards. It takes 10-20 seconds to turn the system off. The journalist didn't do much research, the owners clearly didn't consult the manual.

It also reminds me of the idiots who drove into the sea at low tide because the sat nav apparently said so.

I love the tech in the Tiguan. It's just dangerous when people don't understand it's function like in the OP and adjust their driving behaviour to misperceptions.

[Nauend]

yeah, the ACC can’t see stationary objects, and will not react to people, animals or cars crossing the lane or coming towards you in the same lane. The front assist can detect some of these, between certain km/h ranges, but its full of limitations too. Maybe one day they will…….. but till then the driver needs to remain in control at all times.

[Guest001]

yeah, the ACC can’t see stationary objects, and will not react to people, animals or cars crossing the lane or coming towards you in the same lane. The front assist can detect some of these, between certain km/h ranges, but its full of limitations too. Maybe one day they will…….. but till then the driver needs to remain in control at all times.

Does react to car crossing as I had one pull out from side of the road and do a U turn right in front of me the first week I had my Passat in 2010. Bloody thing stopped dead before I could hit the brake and it was an earlier version of Front Assist. Some now have pedestrian avoidance as well including the Tiguans

[Nauend]

Does react to car crossing as I had one pull out from side of the road and do a U turn right in front of me the first week I had my Passat in 2010. Bloody thing stopped dead before I could hit the brake and it was an earlier version of Front Assist. Some now have pedestrian avoidance as well including the Tiguans

yeah the front assist will pick those up if you travelling within the speed range where the car will detect that. my car has put done the emergency braking once - it picked up the tail of a bus in the next lane as the bus swung out to turn a corner off the road - glad to have seen what it’s like when the car brakes with the red warning dash message, and happy to know it’s there (and hope I don’t need to experience that again!). My car has recently put on the brakes as I back out of the garage - still working through what I am doing or what the car is seeing for it to do that!

[Guest001]

yeah the front assist will pick those up if you travelling within the speed range where the car will detect that. my car has put done the emergency braking once - it picked up the tail of a bus in the next lane as the bus swung out to turn a corner off the road - glad to have seen what it’s like when the car brakes with the red warning dash message, and happy to know it’s there (and hope I don’t need to experience that again!). My car has recently put on the brakes as I back out of the garage - still working through what I am doing or what the car is seeing for it to do that!

If your driveway is sloped it could read the road as an impediment as it approaches it

[Suncoaster]

I have had my T-Cross stop dead at a drainage grate in the middle of a shopping centre car park. No big deal, but I thought that I had hit something at the time. Cheers-John

[Odin]

The radar that ACC uses is based on Doppler chirping radar. A characteristic of all Doppler radars is that they can only 'see' other objects when it has relative motion. Stationary objects are effectively invisible to Doppler. So it wouldn't have mattered if lanes were changed into the path of a stopped car, a brick wall, or a fallen roadside sign - they'd all be 'invisible' to the ACC's radar.

For a radar to detect a stopped car, and further discriminate against other harmless stationary roadside fixtures like armco barriers etc. would take some serious computing horsepower and a considerably more advanced radar to reliably achieve.

[Guest001]

The radar that ACC uses is based on Doppler chirping radar. A characteristic of all Doppler radars is that they can only 'see' other objects when it has relative motion. Stationary objects are effectively invisible to Doppler. So it wouldn't have mattered if lanes were changed into the path of a stopped car, a brick wall, or a fallen roadside sign - they'd all be 'invisible' to the ACC's radar.

For a radar to detect a stopped car, and further discriminate against other harmless stationary roadside fixtures like armco barriers etc. would take some serious computing horsepower and a considerably more advanced radar to reliably achieve.

Yeah those of us who have read and found that out know but most arent aware and therefore think its a fault The guy whose car stops because driveway probably slopes and it sees the perceived upslope of the road is stopping because the rear traffic alert is activated

[fatjoez]

The radar that ACC uses is based on Doppler chirping radar. A characteristic of all Doppler radars is that they can only 'see' other objects when it has relative motion. Stationary objects are effectively invisible to Doppler. So it wouldn't have mattered if lanes were changed into the path of a stopped car, a brick wall, or a fallen roadside sign - they'd all be 'invisible' to the ACC's radar.

For a radar to detect a stopped car, and further discriminate against other harmless stationary roadside fixtures like armco barriers etc. would take some serious computing horsepower and a considerably more advanced radar to reliably achieve.Excellent contribution thanks Odin for clarifying.

Interesting that Tesla has switched to Camera based system rather than radar which will heavily increase the computing power required.

I expect mainstream radar tech and computing will accommodate stationary vehicles by 2025-30 since industry guidance is we will have full autonomous by then.

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[Nauend]

Yeah those of us who have read and found that out know but most arent aware and therefore think its a fault The guy whose car stops because driveway probably slopes and it sees the perceived upslope of the road is stopping because the rear traffic alert is activated

Nah it’s not my driveway - that’s flat. Am thinking the front assist has been picking up the side of the garage as I reverse out and turn slightly as I'm reversing.

Just read about chip Intel is developing that can do 176 trillion transactions per second to support the sort of decision making autonomous driving needs:intel's mobileye autonomous driving chip (https://techcrunch.com/2022/01/04/intels-mobileye-autonomous-driving-chip-for-consumer-vehicles/). there is also a good video on how the Waymo autonomous car (https://www.youtube.com/watch?v=B8R148hFxPw) operates and uses radar and cameras to self drive.