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How does autopilot cope with bends/slippery surfaces?

Discussion in 'Model S' started by Wh05apk, Jul 31, 2016.

  1. Wh05apk

    Wh05apk New Member

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    Unfortunately not a problem I will have anytime soon, but just wondered how ap copes with bends etc, does it slow down for them, or will it just try to "force"the car around at the set speed?
    Following on from this, how does it cope if it loses grip, presumably traction control/stability control etc will cut in, would it countersteer?
     
  2. brkaus

    brkaus Member

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    Hopefully one doesn't use it on a slippery surface on purpose.

    It does slow in corners. Or it asks the driver to take over.
     
  3. mspohr

    mspohr Active Member

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    The AP will slow down on curves. The amount of slowing has varied with different releases of the software. The current release is very good... if anything a bit over-cautious.
    As far as slipping on wet/snow. I have an S85D and it has been amazingly stable. I have yet to have it break loose (but I usually drive cautiously). I've never even felt it slip. (I did have a loaner P85 once which was a bit squirrely on curves under heavy acceleration so the D versions are better.)
    Once when we had about 6" of wet snow/slush, I found a deserted road and tried to get the car to slip. I floored the go pedal and all I got was steady acceleration in a straight line. I then slammed on the brakes and only got steady deceleration in a straight line.
     
  4. CHG-ON

    CHG-ON Still in love after all these miles

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    Just to be clear @mspohr, Did you use AP on slippery surfaces? I have not yet had the chance and am intetested. I concur on slowing very well on curves. Works like a charm.
     
  5. mspohr

    mspohr Active Member

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    Rain only. Not on snow.
    Very stable on wet surfaces.
     
  6. green1

    green1 Active Member

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    The manual, like that for every cruise control ever made, explicitly says not to use AP in slippery conditions. Same with tight corners. It's designed for freeway driving.
     
    • Informative x 1
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  7. brucet999

    brucet999 Active Member

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    Curving roads, AP performs very well, slowing enough to make the turn comfortably. It seems to ignore the yellow advisory speed signs, taking curves at well above that speed.

    "Counter steer"? Seriously? If you want something to drive for you in icy conditions and steer out of a skid, hire a professional driver. :)

    Even on winding roads I usually steer myself so I can enjoy the sure cornering of a great car and I can cross the center line to cut off inside curves, where visibility allows.
     
  8. ABCCBA

    ABCCBA Member

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    I have been experimenting with AP since I got my car. I have a 85D. The wheels have yet to lose traction in rain or sand. I tried AP while it was raining. I had the steering wheel in my hand and my foot was covering the pedals. I specifically put the car in the lan were I saw a large puddle of water. Once the car hit the puddle and the force of the water started to slow the car down, AP aborted and I took over control. However, at no time did I lose traction.

    I have not seen AP slow down any while taking turns.
     
    • Informative x 1
  9. Derek Kessler

    Derek Kessler Member

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    I just drove today through both of those conditions on I-70 in the mountains west of Denver. Very very curvy highway plus train.

    Curves: Autopilot will slow down if the curve calls for it. Frequently it'll show before the curve, occasionally it realizes it's taking it too fast and slows partway through the curve.

    Rain: First off, it's not advised to use Autopilot in inclement weather for the same reason you're told not to use cruise control: the car cannot handle events like hydroplaning on its own. Granted, we humans aren't great at it either, but it absolves the automaker of liability.

    That said, Autopilot handled itself quite well in the rain. Certainly the weight of the car and that I'm driving a D model didn't hurt with maintaining traction on the twisty wet highway.

    In fact, the only issue I had with Autopilot in the rain was visibility: it briefly rained hard enough that the camera couldn't confidently discern the lane markings on the road and Autosteer disengaged.
     
  10. Shawn Snider

    Shawn Snider Member

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    Learning Safely! :)
     
  11. ABCCBA

    ABCCBA Member

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    One other thing, AP has a great tendency to abort while making a sweeping left hand, off-camber turn. I imagine it is because the camera loses sight of the right side lane markings. This can be very hazardous if you are not expecting it! Imagine what happens to the car when making a left sweeper and the AP disengages. If you don't know, the wheels automatically straighten, while the road is still turning left. In other words, AP dumps, the car straightens its path and 'jumps' to the right lane or worse yet, the right shoulder.

    Since AP is a hands on driving assistant, and if you take the time to learn the pros and cons of the system, this action should not be alarming. But, if you are part of the careless and inattentive drivers on the road, you will end up in the guardrail or ditch very quickly.
     
  12. brucet999

    brucet999 Active Member

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    Not a lot of mountain roads in Florida. :)

    Those of us who have experienced AP slowing in curves have been on winding roads whose curves require slowing from 60 to 45 or sometimes slower in order to make it through.
     
  13. Caboom

    Caboom Member

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    Maybe this isn't the correct thread...

    How does AP integrate with navigation and when navigation alerts that there is a fork or split in the highway and car needs to change lanes to continue on correct navigation route...
     
  14. brkaus

    brkaus Member

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    It died not interact at all.
     
  15. brucet999

    brucet999 Active Member

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    That may come in "Summon ver 12.xx" when, as Elon jokingly tweeted, we can summon our cars from CA to NY; after automated SpCs are installed, of course. :)
     

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