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Shifts to Park when Butt Lifted from Seat?

Discussion in 'Model S: Driving Dynamics' started by mknox, Nov 26, 2012.

  1. mknox

    mknox Well-Known Member

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    Saw a video review of Model S and the reviewer stated (and demonstrated) that when he was backing up and twisted around to look over his shoulder, his position in the seat changed and the car jerked to a stop. (About 4:50 mark here).

    This does not seem like a very safe thing for the car to do, and I'm wondering if it was some sort of defect on the test vehicle. It seems to me that if the car is in Drive or Reverse, and is moving, the seat sensor should be disabled. A normal ICE will not throw itself into Park like that. I sometimes adjust my seating position by pressing my arms down on the armrests and sliding my butt into a more comfortable position, and I certainly wouldn't want the car suddenly jerking to a stop on the freeway.

    Wondering if any current Model S owners have seen this behavior?
     
  2. AnOutsider

    AnOutsider S532 # XS27

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    I'd be interested to know as well. Perhaps it's speed-dependent. i.e. it won't shut off if you're going over X MPH?
     
  3. Zythryn

    Zythryn MS 70D, MX 90D

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    Agreed, I would love to see details about this.
    That said, in 7 weeks of driving neither my wife nor I have experienced this. I would suspect that normally this is disabled at a certain speed and/or the 'test' shown was staged.
     
  4. NigelM

    NigelM Recovering Member

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    IMO this is a great safety feature!

    As for the video, the back of the car is high and the rear window doesn't have great visibility so why didn't the reviewer just use the back camera? He could easily have backed over his neighbors cat otherwise.
     
  5. ckessel

    ckessel Active Member

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    This behavior sounds dangerous for anything other than a stopped car. Having the seat detection glitch at highway speed, say because I lifted myself up a bit with the armrest to reset the angle of my aching back, would be catastrophically dangerous.

    I also lift up somewhat to look out the rear window. One, it'll be habit since I've never had a backup camera. Two, the camera would only ever be a data point I keep in mind, I trust my own eyes. I also don't purely trust the mirrors when changing lanes, I always physically glance.
     
  6. NigelM

    NigelM Recovering Member

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    Not sure how you keep your foot on the accelerator and cover the brake, keeping both hands on the wheel while lifting yourself completely off the seat at highway speed. That sounds pretty dangerous to me also.

    Unless you're a lizard you can't look forwards and backwards at the same time. With Model S (like many other cars) it's impossible to see what's on the ground behind the car if you don't use the camera. With a car as quiet as Model S you really want to watch the camera to avoid small children and animals.

    Agree 100%. I do the same thing.
     
  7. AnOutsider

    AnOutsider S532 # XS27

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    Honestly, I don't drive with both hands on the wheel, and there are indeed times when you may need to lift. For example, if I'm in a car that doesn't have my EZ Pass, I lift (while driving) to get my wallet so that I can be more prepared once I hit the booth. I've also had to lean back and grab something from the back pouch of the passenger seat while driving (which won't be a problem in the S, since it doesn't have one). Sure, the argument could be made that these aren't "safe" things to do while driving, but you can't deny that having the car shift into park while doing those things (if that's what happens) isn't a whole lot worse.

    I also check mirrors and physically look (we even have blind spot detection, but I don't fully trust that), but I also don't 100% trust my backup cameras either. The Model S may indeed end up being harder to see out of, but I don't think the "look back" habit will die easily. Heck, during my driving test I got dinged for backing up while watching the mirror. I passed, but that's always stuck with me.
     
  8. mknox

    mknox Well-Known Member

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    I think we all do those kinds of things, but just knowing that the car could slam itself into Park while underway is disconcerting to me. In addition to the above, you could spill coffee and zap the sensor, or it could fail for any number of reasons (I've had seat belt seat sensors fail) and cause this behavior. It seems almost unbelieveable that the car would do this, and that's why I wondered if it was a defect on the reviewer's test car.
     
  9. ckessel

    ckessel Active Member

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    That's purely being argumentative for the sake of being contrary.

    AnOutsider handles the response with more grace than I would have, so I'll just say +1 for his answer.
     
  10. DaveVa

    DaveVa Sig Perf #236 VIN #484

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    I think that this is an absolute must on the car - There is no sensation difference between "D" and "P". In my first test drive of a Tesla Roadster, the previous driver left the car in Drive. When I entered the car, I almost put it over a curb (caught it just before). I think that the danger of the car being left is Drive is more likely than sensor failure.

    In the weeks I have had the car, I have never had a problem with it unexpectedly shifting into park under normal use. I would also expect that Tesla would not let this happen at speed; just like it will likely not let you accidentally put it into Reverse when you are moving at speed, if you accidently hit the gear shift.
     
  11. NigelM

    NigelM Recovering Member

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    #11 NigelM, Nov 26, 2012
    Last edited: Nov 26, 2012
    I wasn't actually disagreeing with anything you said in that quote. I stated that a certain action sounded potentially dangerous to me; I'm entitled to a POV just as you are but not everyone who disagrees is being argumentative.

    In any case, I'd be pretty certain that Model S won't stop if you adjust your driving position at speed. So far, the car seems to be clever enough. I'll test it shortly and if I don't report back this afternoon you'll know it slammed me into the steering wheel.
     
  12. Vger

    Vger Active Member

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    A related experience: When I was test-driving the green Performance car out of the Bellevue, WA store a few weeks ago, I accidentally touched the shift stalk while driving slowly and inadvertently shifted the car into neutral. I went to accelerate up a hill, and lost drive, racing the motor, not realizing what I had done. The Tesla co-pilot politely pointed out my error, and no harm done. But I was shocked how easy it was to do that. I was habitually reaching for the wiper control (it is on the right-hand side in all other cars I have driven recently).

    Anyone else had this happen?

    Once again, there is little reason to allow shifting into N in a moving EV. I think they need to disable that stalk completely at speed. The Roadster has this safety, complaining "Unsafe Gear Change" if you do it accidentally.

    The car was running the most current firmware at the time, BTW.
     
  13. mnx

    mnx 2013 P85

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    useful for hypermiling? (ie. no regen so you can coast farther)

     
  14. Vger

    Vger Active Member

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    True, but still too easy to do inadvertently. If it is allowed at speed, I would make it so you need to double-click or something.
     
  15. jkirkebo

    jkirkebo Model S P85+ VIN 14420 EU

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    You can't race the motor in neutral, it is always connected to the wheels. No clutch of any kind exist to disengage it.
     
  16. doug

    doug Administrator / Head Moderator

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    This is what I was going to point out. Basically nothing should happen.
     
  17. Doug_G

    Doug_G Lead Moderator

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    As for lifting off the seat - shifting from D to P is disallowed above a certain speed. Normally you would also need to have your foot on the brake. I'm sure there's a limit of a few mph above which this wouldn't happen.
     
  18. NigelM

    NigelM Recovering Member

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    OK, I survived: Model S does NOT shift itself into park if you lift your butt off the seat when you're reversing and it doesn't do that if you lift your butt off the seat at 60mph either (I tested it on a private road). I also lifted myself completely using the armrests to make sure the sensor wasn't in the back of the seat. If you are operating the foot controls the car will not shift gears automatically.

    Just for fun: On my flat driveway I put the car in "D" and exited the car upon which it turned itself off. Same thing if you leave the key in the car, leave it in "D" or "R" and exit the driver seat. This car is smart! :smile:

    That should be the end of this thread.
     
  19. doug

    doug Administrator / Head Moderator

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    I think the car automatically going into park is a good safety feature. Just maybe need to adjust the parameters that allow that to happen. Vehicle speed, perhaps an open door as well as butt off the seat.
     
  20. Tommy

    Tommy Member

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    I didn't think it possible to race the motor as my understanding is the motor is always "in gear", can you elaborate the sensation you got that made you believe the motor was racing? Thanks.
     

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