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Automatic emergency braking for... railroad tracks?

Discussion in 'Model S: Driving Dynamics' started by jgs, Dec 14, 2015.

  1. jgs

    jgs Member

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    Yesterday I had automatic emergency braking kick in just as I was about to cross a set of railroad tracks. I was going downhill toward the tracks, and I suspect the radar got a strong return off the steel tracks and misinterpreted it as a car ahead. There were no actual cars as far as the eye (or camera) could see. One confounding factor is that I had TACC engaged at the time, however it's my understanding that automatic emergency braking is independent of TACC so presumably the radar is active regardless.

    I didn't use the in-car bug reporting because my passengers were already slightly freaked out and I didn't want to compound it. I may go try to reproduce the problem later.

    Anybody else encountered this kind of problem with tracks or other large pieces of metal embedded in the road?
     
  2. Max*

    Max* Autopilot != Autonomous

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    How do you know it was AEB and not TACC slowing down?
     
  3. jgs

    jgs Member

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    The frantic beep-beep-beep and red collision warning.
     
  4. spottyq

    spottyq Member

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    I seem to remember having seen a post about AEB and railroad tracks on the forum a few months ago, but my google-fu seems to be lacking today.
    Perhaps someone else knows where it is hidden ?

    If I recall correctly, the conclusion was that there was nothing that could be done against that, except not using TACC when crossing such intersections (downhill towards railroad tracks.)

    Curious to see if you can reproduce.
     
  5. jgs

    jgs Member

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    I wonder if disabling TACC would even make a difference, since isn't AEB supposed to be active all the time, unless explicitly disabled? And of course unlike TACC, AEB isn't designed to be easy to flip on and off, you have to drill through menus on the 17".

    I'll report back if I'm able to reproduce the problem.
     
  6. dirkhh

    dirkhh Middle-aged Member

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    I had AEB (wasn't driving with TACC) kick in on Saturday in heavy rain in the middle of an intersection. Nothing but tons of spray ahead of me. It's not an area I drive in often, it's possible that there are old railroad tracks in the road (there's a rail road parallel to the road...) but I was certainly not happy (and my kids in the car got upset).

    By and large I am not happy with the sensors and the cars false positives (which is a big reason why I'm still on 6.2 - figured I should mention this in the context of the false positive report)
     
  7. Matias

    Matias Active Member

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    Did the car actually brake or just gave you warning?
     
  8. dirkhh

    dirkhh Middle-aged Member

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    Beeped loudly, braked hard. I tapped the accelerator and to get us back to regular speed and prevent myself from being rear-ended (but thankfully traffic was fairly light).
     
  9. Max*

    Max* Autopilot != Autonomous

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    Are you saying that v7 has more false positives? I've never had a false positive for AEB on v6 or v7.
     
  10. dirkhh

    dirkhh Middle-aged Member

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    No no no... sorry if this was misleading, not my intention.
    I'm not happy with the sensor input and car response in 6.2. I have frequent issues with blind spot detection, speed limit detection and not so frequent but fat more scary with accident avoiding / AEB (three times total where it braked hard for no good reason, a couple dozen where it beeped for no good reason).
    I take this lack of trust in their sensors and the software team's ability to do useful things with the sensor data plus my intense dislike for the new UI as reason to stay on 6.2.
    So I wanted to state that the false positives that I reported were on 6.2, not on v7.

    Makes more sense now?
     
  11. jgs

    jgs Member

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    For what it's worth I've had many fewer false positives with v7 that I did with 6.2. Although, this is the only AEB false positive I've ever had, the others I'm thinking of were all TACC-related.

    Obviously not something you can base a statistically meaningful conclusion on, but on the other hand it would be surprising if they hadn't improved their ability to interpret sensor data.
     
  12. Stoneymonster

    Stoneymonster Active Member

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    All of the sensor behaviors in v7, including blind spot warnings, parking alerts and collision warnings are much improved from 6.2 in my experience.
     
  13. wk057

    wk057 Senior Tinkerer

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    Interesting. I've had false positives with the collision alert thing, but never any false hard braking. v7.0 2.7.77 currently. Specifically there is also a road nearby similar to the OP where there is a downhill portion that has some railroad tracks at the bottom where it levels out. Never any issues there either.
     
  14. Max*

    Max* Autopilot != Autonomous

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    I gotchya, that I can understand.

    Graphics/UI are very subjective, but the blind spot detection in v7 is significantly better than v6 (I feel this is more objective, and many members here have mentioned).
     
  15. mikeash

    mikeash Active Member

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    This doesn't necessarily mean that AEB kicked in. The frantic beeping and warning means forward collision warning activated, but the braking could have just been TACC. I've had the warning activate in relatively benign circumstances on the highway when, for example, somebody cuts in front of me fairly close. The warning goes off (I have mine set to the most sensitive setting) and TACC brakes mildly at the same time.

    Sounds like your car braked pretty heavily, in which case that's probably AEB. I just wanted to point out that seeing the warning simultaneous with braking doesn't necessarily mean it was AEB if you have TACC engaged too.
     
  16. jgs

    jgs Member

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    It braked (broke?) heavily. The cartoon of the "car" I was "about to run into" was shown very close. ISTR that isn't the graphic shown when FCW kicks in. (I don't have either AEB or FCW kick in often enough to be at all used to them, so I'm not completely sure.)
     
  17. CHG-ON

    CHG-ON Still in love after all these miles

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    I get AEB when I already have my foot on the brake and am slowing as I approach a car. Very annoying. Though it did pay off once when I was yaking too much with my passenger....
     
  18. dirkhh

    dirkhh Middle-aged Member

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    Do you get just the beeping or does it actually slam the brake (automatic emergency braking)? The warning is annoying, but whatever. What freaked me out where the three times (so far) where it slammed the brakes for absolutely no reason I could comprehend...
     
  19. S4WRXTTCS

    S4WRXTTCS Active Member

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    Same experience here. All the alerts are considerably better in V7. Now I should add that they're by no means perfect, but it's certainly improved.

    I haven't yet encounter what the OP encountered, and if I do I'm going to test it over, and over again. To get documentation on it. The purpose of having both the Camera and the Radar is not to get tricked out by one thing. But, with rail road tracks at a certain angle that might be near impossible.
     
  20. Matias

    Matias Active Member

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    Have you set collision warning to late?
     

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