TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Is TACC/AP supposed to detect stopped cars in your lane?

Discussion in 'Model S: User Interface' started by caps04, Oct 23, 2015.

  1. caps04

    caps04 Member

    Joined:
    Aug 14, 2014
    Messages:
    237
    Location:
    NJ USA
    Since buying my car, I have never once had my car detect, slow down or stop for a car stopped at a traffic light or traffic jam in my lane. Maybe it might have but I never waited that long. Just to be sure, I have tested it to the point where I had to brake so hard, things flew forward - so even if it works after that point, it's not practical for me.

    Btw, it works perfectly if the car is moving in front me - just never gets a lock on a stationary car if I am approaching it at a non-trivial speed (40 MPH or more).

    Is my front facing radar somehow busted? I wouldn't think so because in all other situations it works perfectly. Or is this how it's supposed to work?
     
  2. Stoneymonster

    Stoneymonster Active Member

    Joined:
    Jan 8, 2013
    Messages:
    1,554
    Location:
    Aptos, Ca
    TACC did not claim to and most of the time would not. I don't know if that's changed with AP, but probably not. For what it's worth, on my car it often does stop reasonably, but I don't think that means there's anything wrong with your car.
     
  3. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Unless the car previously saw the object moving, it will not, and that's to prevent the car from seeing another stationary object (say, on the side of the road) as another car and suddenly stopping you.
     
  4. CHG-ON

    CHG-ON Still in love after all these miles

    Joined:
    Jun 24, 2014
    Messages:
    2,754
    Location:
    Santa Cruz Mountains, USA
    Mine always stops. Even when I am rolling up behind somebody and engage it maybe 10 ft back. It locks on instantly and stops, then follows. I use it every day and practically never have to touch the brake myself. I think I might be misunderstanding the question.
     
  5. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    I read it as he was travelling up the road and there was a stationary car ahead that hadn't been seen as moving by the car previously. So you come around a slight curve to find a car stopped at a red light ahead (that the car hadn't locked onto previously). I don't think Model S TACC has ever slowed down for that (although it's likely to engage emergency braking when you get really really close).
     
  6. JenniferQ

    JenniferQ Member

    Joined:
    Sep 13, 2015
    Messages:
    974
    Location:
    San Diego, CA
    Mine always stops as did the TACC (Dystronic) in my past two MBZ going back 5 years now, so TACC certainly should.
     
  7. yoyo

    yoyo Member

    Joined:
    Nov 14, 2014
    Messages:
    103
    Location:
    IL, USA
    I think it changed with AP. when auto steering is active and it goes into red light with stopped cars which was not detected before, it would slow down and stop
    but do not try this with curve as it will detect it too late and slam on brake.
     
  8. JenniferQ

    JenniferQ Member

    Joined:
    Sep 13, 2015
    Messages:
    974
    Location:
    San Diego, CA
  9. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Ah, yes, I would expect it changes with later AP... My experience with TACC is limited to loaner use until I get the X.
     
  10. CHG-ON

    CHG-ON Still in love after all these miles

    Joined:
    Jun 24, 2014
    Messages:
    2,754
    Location:
    Santa Cruz Mountains, USA
    I just tested it on my way home. A car was stopped at a light about 15ft ahead of me. I engaged just TACC and the car stopped as always. Though I can certainly see if I were travelling at speed and came around a tight curve upon a stopped car, it could have a problem. But so far, even when driving with nobody ahead of me, when I encounter another car, moving, from around a curve, TACC locks on immediately and tracks. I've only had one real issue where it slammed the brakes on when it shouldn't have. Scared the crap out of me. I reported to Tesla right away. That was back when it was first released. No problems since. I'm actually surprised at just how well it works. I'm still figuring out AutoSteer. It can do some funky stuff on surface streets, which I would expect. The highway has been great so far.

     
  11. RDoc

    RDoc S85D

    Joined:
    Aug 24, 2012
    Messages:
    1,569
    Location:
    Boston North Shore
    It always stops for me, even at highway speeds and regardless of if it ever saw the car moving. It was very abrupt at first, but each update has noticeable improved the smoothness.
     
  12. lorih

    lorih Member

    Joined:
    May 12, 2013
    Messages:
    692
    Location:
    Silicon Valley/ Seattle Areas
    A few things to check:
    1) make sure your TACC is set for the proper distance. It might not stop for the distance you like.
    2) if it really gets to the point where it is too close to stop it should give you a collision mitigation warning and it should emergency break for you.
    3) make sure it seeing the car in front of you. If you have manually engaged TACC then you should see a replica on the dashboard of what it 'sees'. If you turn it on and it doesn't see anything to track it should be pale grey, not white or blue.

    If this all working, but still not stopping, I would bring it to the service center to check.

    Disclosure: these are the things I learned as a passenger with someone else driving, so I don't know how it "feels", just what the driver tells me.
     
  13. tezzla

    tezzla Member

    Joined:
    Jul 14, 2013
    Messages:
    544
    Location:
    SoCal
    From the manual:

    Warning: Traffic-Aware Cruise Control can not detect all objects and may not brake/decelerate for stationary vehicles, especially in situations when you are driving over 50 mph (80 km/h) and a vehicle you are following moves out of your driving path and a stationary vehicle or object, bicycle, or pedestrian is in front of you instead. Always pay attention to the road ahead and stay prepared to take immediate corrective action. Depending on Traffic-Aware Cruise Control to avoid a collision can result in serious injury or death.
     
  14. Stoneymonster

    Stoneymonster Active Member

    Joined:
    Jan 8, 2013
    Messages:
    1,554
    Location:
    Aptos, Ca
    That's that one! Thanks for finding this.
     
  15. caps04

    caps04 Member

    Joined:
    Aug 14, 2014
    Messages:
    237
    Location:
    NJ USA
    You mean the TACC car length setting? I usually keep it around 3. I'll try to set it to 7 and see if it works better. There is also a setting for Collision warning/Automatic braking in Settings screen which I have played with without seeing any difference.

    - - - Updated - - -

    I remember reading this but I've seen many people claim that it should still work (at least occasionally) and mine never did. Anyway, with this disclaimer, I don't expect service to even look at it because otherwise it works fine.
     
  16. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    To reply to the OP's question: of course it is designed to stop for cars stopped or stopping in front. If not it would be designed to drive through them (highly unlikely). And yes, if the car can see and measure it's differential speed to something in front then I'm confident it won't have an issue measuring the relative speed and distance to something that happens to contribute 0 to the relative equation. The car doing the measuring is moving anyway, so the delta will be even if measured object's speed is 0.
     
  17. Stoneymonster

    Stoneymonster Active Member

    Joined:
    Jan 8, 2013
    Messages:
    1,554
    Location:
    Aptos, Ca
    This is at least historically incorrect, as several early videos and incidents demonstrate.
     
  18. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    But what then could explain that technically?
     
  19. LetsGoFast

    LetsGoFast Active Member

    Joined:
    Oct 13, 2014
    Messages:
    1,342
    Location:
    Virginia
    Stationary objects are much more difficult to classify than moving ones. Radar can easily confuse an overhead sign for a parked car (as an example). I think the car's ability to detect stationary objects and be certain that they are cars has gotten steadily better over time, but it remains a much more challenging technical problem than detecting moving cars.
     
  20. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    Of course you're right. I understood it by thinking like this: in the "other object speed" range 0 it's very crowded with objects as opposed to any other speed (faster or slower than 0).
     

Share This Page