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What makes autopilot auto adjust to speed limit?

Discussion in 'Model S' started by fasteddie7, Mar 18, 2017.

  1. fasteddie7

    fasteddie7 Member

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    uniontown PA
    I have my autopilot set to +5 relative and on my commute to work the speed limit changes between 35 and 50 several times. Sometimes I notice when the speed limit changes up (35 to 45 for example) autopilot will automatically accelerate up to match, other times it will stay at the old limit causing me to pull back on the stalk to manually make it accelerate. It always adjusts down, but I can't seem to find a reason on when it does vs when it doesn't. Anyone have any input? I have an AP1 vehicle.
     
  2. BerTX

    BerTX Active Member

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    It will only adjust up to the highest setting you have set. That doesn't make sense without an example.

    If you start AP while the speed limit is 40, it will adjust down automatically to the speed limit change (+5), but will only adjust back up to 40 (+5). If the speed limit goes up to 50, it will not automatically adjust any higher than the maximum you have set previously.

    And of course it is NOT adjusting to the speed limit. It is limiting the speed that you can use AP over the speed limit on an undivided road.
     
    • Informative x 2
  3. fasteddie7

    fasteddie7 Member

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    Location:
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    There are a few times I have to take over from autopilot so I'm guessing it then resets to the highest speed being reset when I re-engage it. So if i understand correctly, if it's at 50 and drops to 40, the next time it hits 50 it will auto accelerate. If I took over while it was 40, it will not accelerate over 40 without me manually setting it again.
     
  4. RichardD

    RichardD Supporting Member

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    Location:
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    If it can see the speed limit sign change is what I notice. Sometimes the sign is at a bad angle, or a car blocks its view. I thought it was GPS related but I have seen it change speeds at the exact moment it passed the sign. I'll try and take a picture on AP1 it looks like it has the symbol for the sign, but I might be imagining it..
     
  5. BerTX

    BerTX Active Member

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    I think it will recognize the speed limit when you set AP as the top speed. I'm not sure about manually bumping it higher when the speed limit goes up, whether that now becomes the new max -- i assume so. I usually don't restart AP until I'm back on an open highway, after the speed limit is back up to normal.

    Interestingly, if you are on TACC only with no AS, you can hold the speed control stalk toward you through a small town and the car will slow to the speed limit (+5) as you enter town, then speed back up as you leave. Not useful, but interesting.
     

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