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TACC Disabling in Tunnels. Why?

Discussion in 'Model S: User Interface' started by Todd Burch, Feb 9, 2015.

  1. Todd Burch

    Todd Burch Electron Pilot

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    The last week or so I've driven several times through a tunnel near where I live (about 1-2 miles long, descending about 80 ft below the surface of the Chesapeake Bay). Anyway, like clockwork, TACC always disables within about 30 seconds of entering the tunnel. I get a "Cruise not available" message. This has happened 3 times (every time I've driven through it).

    My question is--why? What about the tunnel is shutting down the cruise? The driving and road condition isn't any different.

    Two theories:

    1) The increased pollution from ICE exhaust in the tunnel is causing issues with the radar. (This seems most plausible, although I have a hard time believing that exhaust would cause enough of a radar signature to cause issues).

    2) The camera is somehow involved in the TACC system, and it's getting confused by the lighting conditions.


    Any thoughts?

    By the way, I've read that a lot of people reboot the touchscreen when they get a "cruise not available" message while using TACC. I've found that simply toggling cruise off and then back on (using the button at the end of the stalk) is sufficient to reset the system and begin using it again (given that the condition causing the error has gone away).
     
  2. Stoneymonster

    Stoneymonster Active Member

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    Most likely tons of reflections off the walls for both the radar and the ultrasonic proximity sensors are confusing it. The front camera is also used to identify cars I believe but I suspect it's not the issue.
     
  3. mrElbe

    mrElbe Member

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    No GPS in the tunnel might be the trigger factor.
     
  4. wk057

    wk057 Senior Tinkerer

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    The RADAR will work fine through smog.

    The problem will be echos of the radar off of the walls of the tunnel and the same for the ultrasonics. It will get confused to the point where there is not enough input for it to safely make a determination (loss of RADAR and ultrasonics due to the echos leaves only the camera, which would not be an accurate input for ranging the car in front). At that point the safest thing is to give control back to the driver.

    This is just a theory. A very plausible theory, however.
     
  5. Denarius

    Denarius Active Member

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    I vote GPS as well. Probably tied to it for autopilot, even though it's not really used yet.
     
  6. bylund

    bylund Member

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    I've been driving through several long tunnels (several miles) using TACC without any issues, so I doubt it the GPS, as it definitely lost signal in those.
     
  7. Todd Burch

    Todd Burch Electron Pilot

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    Ok, going on the reflection on walls theory, has anyone lost TACC simply going through an area that has a high wall on one side of your lane? (The tunnel I was driving through was two lanes each direction, so only a wall on one side.
     
  8. AmpedRealtor

    AmpedRealtor Active Member

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    Could it be sodium vapor lights interfering with the radar frequency somehow?
     
  9. wk057

    wk057 Senior Tinkerer

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    It could also be radar in the tunnel to catch speeders that interferes...
     
  10. youyouxue

    youyouxue Member

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    I would vote for the GPS or camera theory.

    Radar is shot forward in a narrow beam, and it would be highly unlikely that it would bounce around the tunnel to come right back and confuse the vehicle.

    Is this in every tunnel? Have you tried driving when there is less traffic? Have you tried driving in a wider tunnel?

    The frequency for cop radars are different from TACC radars. Frequencies are very well regulated, and radar manufacturers agree on certain frequencies to avoid such interference.

    I don't believe the TACC checks the blind spots though, so it may just be relying on front-facing instruments (radar and camera).

    Cheers,
    You You
     
  11. Todd Burch

    Todd Burch Electron Pilot

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    For the record, I drove through several tunnels with TACC active yesterday, and it performed without issue in all of them. So it looks like this issue has been fixed in a recent software update.
     
  12. llavalle

    llavalle Member

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    Same here. Went through a 1mile tunnel 2 times last weekend, on auto-pilot, in a traffic jam. Worked A1. It was a 3 lanes tunnel on the south shore of Montreal.
     
  13. Cerie

    Cerie Member

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    Works in the Baltimore tunnel just fine for me.
     
  14. saladman

    saladman Member

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    I'm betting it's radar reflections, which the system deems unreliable. My TACc disengaged over the weekend when I got boxed in by two trucks on the left and right side. Whatever the car "saw" it didn't like and returned control to the driver.

    Thats how these things work. You're still the driver.
     
  15. wk057

    wk057 Senior Tinkerer

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    TACC worked fine in the Fort McHenry Tunnel and the Baltimore Harbor Tunnel on my last couple of trips. The very first one I made through there (very first TACC firmware) it cut out near the end of the tunnel and came back a few miles later. No issues since though.
     
  16. RDoc

    RDoc S85D

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    We recently went through the Baltimore tunnel and the TACC went off and stayed off for several minutes after we exited it! That really surprised us.
     
  17. NOLA_Mike

    NOLA_Mike Active Member

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    Went through the Ft. McHenry tunnel day before yesterday and mine disabled near the end of the tunnel as well. Came back on a few miles later.

    A few days earlier I had gone through the I-895 tunnel and it did not deactivate.

    I speculated the forward facing radar is just getting overwhelmed with the returns off all the close quarter walls but I dunno...

    Mike
     
  18. NielsChr

    NielsChr Member

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    Moste likely due to the fact that trafik aware Camera have problems in fast transitions between dark and bright scenes such as tunnel entry and exit.
    It is a isue mobileyes is trying to improve and every new model works better and better.

    SeeQ® - Mobileye
     

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