TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Too close call with TACC

Discussion in 'Model S' started by Jorell, Jul 1, 2016.

  1. Jorell

    Jorell Member

    Joined:
    May 14, 2016
    Messages:
    15
    Location:
    New york
    Have had MS for several weeks now and overall really enjoying the car. Have had lots of very good experience with TACC and AP. Last weekend, was driving in stop and go traffic (up to about 40 mph and down to stop), when the TACC system did not slow down as we approached the car in front of us. The car ahead was slowing down rapidly, but it was not a sudden stop of the car ahead. I waited for the MS to brake/slow down, but it did not - until the collision warning sounded (so, good to know that works!) and I hit the brake, when we stopped very sharply and it got the attention of everyone in our car.

    I assume the system is designed to brake well before the emergency braking system starts to kick in (but good that they seem to be separate . . . ); this was a little scary. The car ahead did not swerve into the lane; i had the follow car length set at 4 car lengths. The only thing I had changed was I had just put an external transponder for EZ pass on the license plate - any chance that interfered with the TACC system? I had generally been watching to make sure that if there was a car ahead of me, it was showing up on the display screen - I assumed that meant that the car ahead was being tracked and the MS would respond as the gap closed.

    Any thoughts? I am a little bit less trusting of the system than I had been.
     
  2. buckerine

    buckerine Member

    Joined:
    May 29, 2014
    Messages:
    139
    Location:
    Ohio
    I've had zero issues with TACC in my time with the car, but I can certainly see how this might've happened. Was perhaps the sun pretty bright and shining in the direction of the camera or creating glare on the road such that the lane markers weren't as visible?
     
  3. jgallops

    jgallops Not so Well Known Member

    Joined:
    Nov 21, 2013
    Messages:
    54
    Location:
    Illinois
    I have my EZ pass transponder mounted the same way. If you look at my avatar, you can see the transponder on the top of the license plate.

    I have not had an issue with TACC so far. (I have had with AP, but so have others.)
     
  4. Jorell

    Jorell Member

    Joined:
    May 14, 2016
    Messages:
    15
    Location:
    New york
    Thanks for the reply folks; MSNOW - great suggestion!
     
    • Like x 1
  5. Jorell

    Jorell Member

    Joined:
    May 14, 2016
    Messages:
    15
    Location:
    New york
    Buckerine - I also had great experience with TACC so far; no issues with sun shining into the camera
     
  6. David29

    David29 Member

    Joined:
    Aug 1, 2015
    Messages:
    564
    Location:
    DEDHAM, MA
    When i have had troubles with TACC, there is usually a message saying it is not operating. It is only a guess what the cause is -- sun, rain, dirt on a detector, etc. And it usually appears immediately upon actuating the system. I have never had it suddenly quit (although it has told me to take steering control).
     
  7. RDoc

    RDoc S85D

    Joined:
    Aug 24, 2012
    Messages:
    1,569
    Location:
    Boston North Shore
    I've got the same transponder on the same location and our TACC works very well, although occasionally it does wait a bit long before slowing down.
     
  8. travwill

    travwill Member

    Joined:
    May 1, 2015
    Messages:
    901
    Location:
    Chicago, IL
    TACC usually works well 99% of the time. I can recall a couple times it hasn't slowed down well though or scared the hell out of me so i've had to stomp on the breaks in cases where its locked on but the car is stopped. It doesn't do well with stationary objects at all ahead thus perhaps if the car is a farther distance, stops suddenly, and your coming up on it, it has issues? Not sure as well.

    I have an i-PASS mounted on plate as well but never thought it has interfered - interesting concept there.
     
  9. DCGOO

    DCGOO Member

    Joined:
    Nov 24, 2015
    Messages:
    234
    Location:
    Indianapolis, IN
    A value of 4, does not correspond to 4 car lengths. It is a relative value of time. The distance varies based upon your speed and how long it will take you to reach the vehicle you are approaching. It might be more like 4 seconds away. I run with mine set to 6 or 7.
     
  10. kavyboy

    kavyboy Member

    Joined:
    Jan 13, 2016
    Messages:
    56
    Location:
    Magnolia, TX
    I've had similar experiences as the original poster. In every case, my foot was resting too heavily on the accelerator, and actually pressing it. My new shoes, for example, make me do this a lot, so I drive barefoot rather than wear them.
     
  11. Larry Hutchinson

    Joined:
    Dec 15, 2012
    Messages:
    93
    Location:
    Beaverton, OR
    I had the same thing happen as the original poster. Driving in stop and go traffic, every thing working just fine and then the car ahead stopped very quickly and my car did not slow down anywhere fast enough and I had to slam on the brakes (as my wife was yelling.) Afterward, she said "why don't you just drive."

    Vin 140742, Father's Day about 6:30 pm or so (in case Tesla is reading)

    Now I know not to trust TACC quite as much.
    (Autopilot was on but this is just TACC)
     
  12. Jorell

    Jorell Member

    Joined:
    May 14, 2016
    Messages:
    15
    Location:
    New york
    Interesting - sounds like at least a few others have had the same experience.

    Larry Hutchinson, fortunately, I had the same safety system working as you did (i.e. LOML in the seat next to me yelling to stop). Worked for my parents for a long time also . . .
     
  13. EVie'sDad

    EVie'sDad Member

    Joined:
    Mar 6, 2016
    Messages:
    344
    Location:
    Newark, CA
    try setting the vehicles following distance to 5, I use that and have no problems. At speeds above 35 a setting of 3 or 4 may not be sufficient to react and slow down. I cannot imagine anyone setting that to 2 or 1. It is the dial on the stalk used for enabling cruise and autopilot on the lower left side of the wheel (at least here in the U.S.).
     

Share This Page