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Adaptive Cruise Fails to Brake to a Stop - Nearly Hits Car!

Discussion in 'New A3/S3 (8V Chassis)' started by BZ888, Jan 2, 2014.

  1. cemerson

    cemerson Well-Known Member

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    It should know where you are driving from the GPS, surely?
     
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  3. constvoid

    constvoid Active Member

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    #82 constvoid, Jan 7, 2014
    Last edited: Jan 7, 2014
  4. Leeber

    Leeber Active Member

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    Some great info on this thread, cheers guys!
     
  5. cemerson

    cemerson Well-Known Member

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    Well, some of the systems (eg, LED lights, static cornering lights) hook in to the GPS for some of their functions, so it wouldn't surprise me. Perhaps it does it if the GPS is there, and uses that as a backup method? As I say, I've not ever noticed it do this.
     
  6. constvoid

    constvoid Active Member

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    OK - this sounds plausible. I don't have SD Sat Nav or the tech pack, so the ACC wouldn't have the necessary maps available to determine LHD vs RHD and would use the patented logic referred to above.
     
  7. royalsteve68

    royalsteve68 Active Member

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    im used to tech, I might be nearly 46 but ive lived in the tech world both in private and business for a long time. Mind you being my first Audi, first auto, ill have a lot to get used to and not trying to change gear the auto selector for starters, lol
     
  8. Kingfisher

    Kingfisher Member

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    haha... same here.
    Daughter got another Sportback a year ago, S Tronic this time. I finally managed to get a drive after a couple on months.... only tried that a couple of times tho' -- she thought it was hilarious !
     
  9. Itguy

    Itguy Well-Known Member

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    I still end up trying to press the imaginary clutch down sometimes in our Golf GTi DSG - we've had it ages!

    Sometimes mind just goes to sleep I think!
     
  10. JohnM100

    JohnM100 #teamSepang
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  11. h5djr

    h5djr Well-Known Member
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    I occasionally do the same and I've been driving with s-tronic for the last 10 years. Mind you I did drive a manual for 38 years before that!!!
     
  12. veeeight

    veeeight I am a very pretty girl
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    So 3 things have caused me to book the car into the dealer.

    Gently sweeping dual carriageway, I was in the outside lane doing 77.1 mph (ahem) - stationary traffic ahead. The ACC did not see this (does not recognise stationary objects) and proceeds to try and continue going into stationary cars at 77.1 mph.

    This is probably a limitation of the system, so not completely unexpected, no doubt pre-sense would have intervened, but at that speed, it would be exciting to say the least.

    I intervened and jumped on the brakes.

    Anyone else not had a stationary Q of traffic being detected?

    And twice now, I've had the "Pre Sense Fault, ACC unavailable" message in the DIS.

    Service technician said that my sensor was dirty (please keep it clean at all times) and it was ever so slightly out of alignment. So he re-adjusted it, we shall see if that has cured it
     
  13. leosayer1

    leosayer1 Active Member

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    Read the handbook.

    ACC doesn't see traffic which is stationary.
     
  14. veeeight

    veeeight I am a very pretty girl
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    Yes.

    It was exciting.

    I appreciate that ACC doesn't detect stationary objects (I said so as much in my second paragraph)

    - but Pre Sense does, and was looking for experiences from others who did get a Pre Sense bing, alert, braking jolt etc. in a similar scenario, at high speed.
     
    #93 veeeight, Dec 13, 2014
    Last edited: Dec 13, 2014
  15. DickiePhitt

    DickiePhitt Active Member
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    Great that this thread has been brought to the top. I was wondering how to test the Pre-sense without totalling the car......still wondering lol

    Seriously, some great information, as always on this forum.
     
  16. constvoid

    constvoid Active Member

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    As you've said, not 'seeing' stationary traffic is a limitation of the system, but you'd also get problems approaching significantly slower traffic when travelling at motorway speeds. I always intervene, either by braking myself if it seems necessary, or by reducing the selected speed so that the system begins to brake, if I see this situation arising. Having said that, it's still possible to get the 'too close' warning going off in some cases, and I'm always on the brake myself as soon as I can when that happens. Remember that ACC is simply trying to keep you a set time behind the car in front, and one point something seconds (for distance 2) isn't enough time to decelerate if the traffic in front is travelling much slower than you, or brakes really heavily.
     
  17. steeve

    steeve Well-Known Member
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    Seems to me that that split second waiting or expecting the car to do its own thing could be the difference between stopping or not. Surely the wise thing would be to always be the driver?
     
  18. cemerson

    cemerson Well-Known Member

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    No, the wise thing is to know the limits of the system and use it within its capabilities to make your drive safer and easier.
     
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  19. cemerson

    cemerson Well-Known Member

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    Pre-sense can warn you when you get close, but it will only work and bring you to a stop under a certain speed (19mph I think from memory).
     
  20. steeve

    steeve Well-Known Member
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    Absolutely and know it may not always work so don't count on it.
     
  21. cemerson

    cemerson Well-Known Member

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    I don't think anyone sensible does!
     
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  23. steeve

    steeve Well-Known Member
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    It's probably not true but ....................

    In November 2000, Mr. Grazinski purchased a brand new 32 foot Winnebago motor home. On his first trip home, having joined the freeway, he set the cruise control at 70 mph and calmly left the drivers seat to go into the back and make himself a cup of coffee. Not surprisingly, the Winnie left the freeway, crashed and overturned. Mr. Grazinski sued Winnebago for not advising him in the handbook that he could not actually do this. He was awarded $1,750,000 plus a new Winnebago.
     
  24. desertstorm

    desertstorm Moderator
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    It isn't true but has the faint possibility of being true seeing it is from America.
    Personally I don't even usually use cruise control let alone ACC , which I don't have.
    I like to keep my attention on the road and what is going on, A lot of the time on the motorway I am looking at what is happening in front of the car I am driving behind, If I see traffic ahead slowing I am already ahead of what an ACC system can do as it's only looking at the gap to the vechicle in front. It won't help you when a deer or other animal appears at the side of the road to run out.

    Long periods of driving on motorways can make it hard to maintain concentration, This system seems to take away the requirement for so much concentration and too me would mean a driver is not as mentally alert as he should be.
    If your not looking in front your probably not even looking behind you for that police car / ambulance coming up behind you or the guy in the white van who has been sitting on your bumper for 5 minutes trying to get you to move over.



    The last 10 seconds of this video is interesting. For legal reasons the Audi braking guard cannot employ full braking performance and it is imperative the driver maintains control of the vechicle.
    For me cruise control is useful when going through speed controlled areas on a motorway, if it's 50 I set the cruise around 53 as the speedo reads high.

    Karl.
     
  25. h5djr

    h5djr Well-Known Member
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    Personally the only time I use the ACC is in a traffic queue or when going through a section of roadworks. The rest of the time I prefer to do my own braking as necessary.
     
  26. constvoid

    constvoid Active Member

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    So what do you think those of us who are using ACC are doing instead of looking around, both front and rear, making sure we're aware of other traffic? We don't suddenly go into a trance just because we let an automatic system take some of the strain of maintaining a safe distance behind traffic ahead - and note that this safe distance is longer than the vast majority of drivers without ACC maintain. I'd hazard a guess that we're at least as aware of what's going on around us as someone without ACC. As i said above, it's always prudent to be aware of what's up ahead so that you can take over as necessary, and as cemerson said anyone using any system must be aware of its limitations and act accordingly.
     
  27. royalsteve68

    royalsteve68 Active Member

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    I have acc and like all tech I don't rely in it, it's an aide and nothing more. Acc is ok but but you are reliant in traffic on nit having an idiot in front who can't drive in traffic eg someone who accelerates hard and stamps in the brakes. I never understand the mentality if these drivers. Keep it smooth and consistent speed and no hard accelerating and braking as it's really easy.
     
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  28. royalsteve68

    royalsteve68 Active Member

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    Agreed it's what I fear when the masses get this tech and forget to use their senses and brain
     
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  29. Martinbanshee

    Martinbanshee Well-Known Member
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    I use ACC to maintain a consistent gap in traffic that varies speed constantly and it's very handy but I switch it off completely if I come across a particularly poor & unpredictable driver. The system would need to have image recognition to distinguish between vehicles and random static objects to able be to slow down safely behind stationary motorway traffic otherwise there would be too many false alarms. If the traffic is moving even slowly it can still be distinguished from a roadside 'ornament'.
    It's a very good system, I'd definitely spec it again.
     
  30. desertstorm

    desertstorm Moderator
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    I refer you to the original poster that started this thread. Obviously there are people who are using this system like an auto pilot who do not understand it's limitations and aren't watching what is going on because they have been caught out , expecting the car to deal with a situation it's not designed to handle. I am not saying everybody will be doing this but reading through the posts from some people there seems to be some ignorance of the systems capabilities and short comings and some people are placing too much faith in it.

    Did a quick google search

    http://www.swov.nl/rapport/Factsheets/UK/FS_Concentration_problems.pdf

    An interesting report, read the section Study of intensity
    Regarding "highway hypnosis" If you don't have a lot to do your attention is taken by other things and you are more easily distracted.
    This is nothing to do with being tired or fatigued. Because people are having to concentrate less on maintaining the speed and distance between them and other traffic then they are more likely to be distracted.
    "we can conclude that the number of traffic errors increases as a result of low intensity of attention"

    Karl.
     
  31. veeeight

    veeeight I am a very pretty girl
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    Yes, if under 19mph, it will activate full autonomous braking, but above 19mph, it should do the "bing" thing, jolt the brakes, then still if no action from you, apply partial braking.

    I was surprised that bearing down on the line of stationery traffic at 77.1mph, it didn't. Or maybe I wasn't brave enough to let it! Need a way to test this.
     
  32. a3_phil

    a3_phil Active Member
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    Private road + Tin foil + 2 trusting friends = youtube gold

    After you of course...
     
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  33. Jerodequin

    Jerodequin Member

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    Watching the video - seems to imply that the automatic emergency braking in only enabled when cruise control is set to on (with or without a speed set) - is this still correct? (kind of pointless if it doesn't work all the time!)
     
  34. veeeight

    veeeight I am a very pretty girl
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    ^ for the A3 range, Pre Sense is active regardless of whether ACC is active or not (in theory, needs testing!).
     
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  35. h5djr

    h5djr Well-Known Member
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    That is the case because last week I was following a car quite slowly along a country lane and when he quite suddenly decided to turn right into a farm entrance and my Pre Sense put my brakes on a split second before I did. Perhaps as I get older my reactions are getting slower !!
     
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  36. cemerson

    cemerson Well-Known Member

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    I've had my pre-sense warnings go off with ACC off before.
     
  37. Martinbanshee

    Martinbanshee Well-Known Member
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    I'm pleasantly surprised that my car easily detects cyclists & motorcycles too.
     
  38. veeeight

    veeeight I am a very pretty girl
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    You'll be pleased to know that the more advanced ACC system in the A6 does just that. It uses 2 radar sensors, plus the monochrome DA camera mounted behind the rear view mirror to input/feed the ACC ECU. That system is capable of much more, including detecting flashing indicator lights of cars in adjacent lanes pulling into your lane, and adjusting automatically.

    The ACC system as fitted to the 8V is a rather more basic version, to keep costs down.
     
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  39. cemerson

    cemerson Well-Known Member

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    The configurator says that the Lane Assist camera enhances the functionality of the AAC in the A3 too, and I believe this to be the case. I'm amazed at how well it can detect which lane the car in front is in (even round corners) etc.
     
  40. veeeight

    veeeight I am a very pretty girl
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    Mine does this too ( when the system is working), and I haven't got a Lane Assist camera !

    I often play the (I wonder if it's going to detect that and slow down) game !

    As you know, on early cars ACC high was dependent on the DA pack, which included the monochrome camera.

    I wonder if the configurator is still the old version, referring to ACC high, which is no longer available.
     
  41. Martinbanshee

    Martinbanshee Well-Known Member
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    I noticed that if someone in front of me that the ACC was tracking moves into the right hand lane of a dual carriageway or motorway and are going slower than my set speed my car will slowly pass them on the inside lane and then accelerate at the normal rate to my set speed. Very good to know that it won't just blast up the inside of a slow moving car on the right. I don't have lane assist or sign detection so didn't expect it to do this. It obviously has a quite a wide detection field to roughly track moving vehicles.
     
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  42. veeeight

    veeeight I am a very pretty girl
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    ^ In this situation, if you do want to resume your set speed (eg: you're on a slip road) - a brief pull on the stalk will give the "go ahead" to "undertake".
     
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