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Fwd collision warning when leaving stoplights

Discussion in 'Model S' started by _jal_, Jan 18, 2017.

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  1. _jal_

    _jal_ Member

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    My AP2 S60 has does this intermittently. I'll be stopped behind a car at a light. The gray fwd collision band shoes on the dash. The light changes, the car ahead starts to go, I take my foot off the brake, then the gray band does the IMPENDING COLLISION!! thing and changes to yellow and red and finally STOP!! Then disappears. During this time the distance between my car and the one ahead of us has actually increased.

    To me it is almost an aliasing thing; the sampling is thinking the car is approaching when it is in fact moving away. I thought that 2.52.120 may have fixed it, but then it happened a few times today. I thought for a while that it was only happening with cars that have ultrasonics, but not so.

    It's of no consequence now, but I hope they figure it out before automatic emergency braking is implemented. I've tried making bug reports, but can't figure out how to do that with voice commands.
     
  2. HX_Guy

    HX_Guy Member

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    Odd, that has never happened to me. Sounds like it may be specific to your vehicle.
     
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  3. Modeler

    Modeler Member

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    "Of no consequence"??? I wouldn't be so calm if this was happening in my car. There is clearly something VERY wrong with the sensors or software. I would take it in for service.
     
  4. ThisIsTrue

    ThisIsTrue Dismember

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    Hold upper right steering wheel button. When it beeps, say "Bug Report" and dictate your report.

    I hear they get a lot of them and don't necessarily review them unless you call in to report it, and note the time of the report so they can pull it up. Not sure if that's a good or bad rumor, but if it's important to you, I'd suggest a follow-up call.
     
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  5. kort677

    kort677 Active Member

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    I had this happen to me twice yesterday, I'm going to guess it is an unintended issue related to the latest software update. other then being a bit jarring there isn't really any other effect.
     
  6. NikeWings

    NikeWings Active Member

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    Same here Kort. I'm usually pretty close in the stop position so when my foot moves off the brake while the car ahead pulls away, I get a momentarily flash/beep. More annoying on the regen to stop position actually, which seems oversensitized with this release. NBD in either case.
     
  7. _jal_

    _jal_ Member

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    Didn't happen at all this morning. It always happens when both my car and the car ahead are accelerating from a stop. If the distance is roughly the same (or only slowly changing) but the cars are accelerating, the round trip echo would be shorter than if the velocities were constant. I wonder if it is interpreting that as a closure of the distance instead of a change of the cars' velocities. There really would be no way to know by just looking at the signals from the ultrasonics.
     
    • Like x 1
  8. Deans

    Deans Member

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    Are you sure your leaving enough following distance as your car accelerates? You should have, say 2 seconds, of following distance at all times. So as you accelerate, the gap between you and the next car needs to widen. If it's staying roughly the same, the car is correctly reporting that you too close to the car in front of you for your current speed.
     
  9. Doubletap67

    Doubletap67 Member

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    I've also had flashes of red from my forward sensors in my AP2 on all builds of the firmware including 2.52.120. Those with the limited preview of AP2 features have reported phantom cars, I believe, and this may be coming from the same buggy interpretation of data. Certainly isn't encouraging that we're very close to actual AP on AP2 hardware cars.
     
  10. _jal_

    _jal_ Member

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    The entire thing transpires over maybe the first two seconds after taking my foot off the brake. By the time it is over, both cars may be going 4-5 mph. I am definitely not closing on the car. The band progresses smoothly from gray to red and the beeps "Stop" and then completely disappears. It definitely isn't a sensical representation of what's happening.
     
  11. Deans

    Deans Member

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    Ok, thanks for the explanation. Does sound like Autopilot 1 parity is a ways off ):
     
  12. _jal_

    _jal_ Member

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    It's really hard to make it happen. Like I said, it seems like both cars have to be accelerating in tandem - not just going at the same speed, but actually accelerating. And maybe doing so at a constant rate. So speed is increasing at a constant mph/s. I'm not really sure because it happens so fast, but it's weird. Still, it obvious that they're not mixing in input from cameras or radar bc that wouldn't tell me to STOP!
     
  13. Drekar

    Drekar Member

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    I suggest the next time it happens you record the date and exact time and report to your SvC. Tesla can use the car's logs to see what was happening.
     

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