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Anyone else find TACC still not trustworthy?

Discussion in 'Model S: Driving Dynamics' started by gordo, Apr 9, 2015.

  1. gordo

    gordo Member

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    I've had a couple recent incidents with TACC enabled that have me questioning whether its reliability.

    The first incident was back in the 6.1 days (believe it was with software .179), where I approached a car slightly ahead of me in the lane to my right that proceeded to put its left turn signal on, then started to move left (still within its lane). Had I not been in TACC, I would have at least taken my foot off the accelerator briefly to give myself a little time and room to judge the intentions of that car as I approached -- standard defensive driving technique that I imagine most experienced drivers would perform. TACC on the other hand ignored the situation as if it weren't happening and simply followed the car directly in front of me at a higher rate of speed. Sure enough, the car in the lane to my right eventually breached the divider line to move into my lane and TACC reacted abruptly with a weak brake (this was pre-Emergency braking) and a beeping collision warning. Having monitored the situation closely with my foot resting above the brake, I easily brought the situation under control with a hard brake action... but not before I was left wondering whether TACC could be trusted in traffic. Fine, I thought... chaulk it up to the immature algorithms in that early TACC implementation.

    Incident two was just the other day. Now running 6.2 (.124), I was driving along with TACC on with following distance set to "5" when traffic in front of me had quickly slowed down on a straight away. TACC seemed to react very sluggishly to the situation and again put on the audible collision warning as it applied a late brake. I didn't wait to see if it would have stopped in time and hit the brakes myself to make sure I could stop in time. Again, isn't the whole point of TACC to avoid such a situation in stop and go traffic in the first place?

    Anyone else having similar TACC experiences?
     
  2. Todd Burch

    Todd Burch Electron Pilot

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    I haven't had issues. The car's always braked in time. Sometimes the pucker factor goes up a bit because I would personally brake a little sooner and less aggressively, but the TACC has always slowed in time for me. I agree the slowing needs to be more gentle.

    Having said that, I'm not sure what you were expecting TACC to do in your first scenario...anticipate that the car waa going to change lanes to the left, and slow accordingly?
     
  3. gordo

    gordo Member

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    Well, if we don't just flat out accept that it has an immature software implementation, I expect a more intelligent reaction to the situation: recognize turn signals in the lanes to my immediate left and right, notice slowing vehicles in those same lanes and also notice a vehicle moving sideways and about to cross a lane marking, then slow down in anticipation of a high percentage hard braking situation.
     
  4. larmor

    larmor Member

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    Like CHAPPiE... system will learn from this experience and compare with other MS... Hopefully it won't drive you to a heist... :crying:
     
  5. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    From reading other TACC threads, this seems to be the normal behavior, with TACC favoring maintaining speed over braking. I suggest that if that's consistent and they don't like it, they contact Tesla to let them know. Tesla does seem to respond to requests, it might be that an option to modify the curve would increase appeal.
     
  6. Todd Burch

    Todd Burch Electron Pilot

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    So you're talking about an implementation that integrates the camera, radar, and sonar. Yeah, they're definitely not that far along yet. Give them some time to integrate that more complicated stuff.
     
  7. Danal

    Danal electricmotorglider.com

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    It is not a matter of trust. TACC in its current form is not intended to handle adjacent lane intrusions before they happen. TACC is NOT "autonomous drive" or "autopilot". Not yet. Just for comparsion, Audi and/or BMW "Adaptive" cruise also would not handle the situation you described.

    Until somebody ships true "autopilot" the driver supervision required for driving on "Traffic Aware" or "Adaptive" includes many, many, many things. Including seeing adjacent lane intrusion before it happens.




    Having said all of that... I was driving 6.2 at 50 to 55MPH on a two lane blacktop, following car in front on setting 3. A pickup jammed his way in between me and the car in front via a side-street turn-in, and then the whole pack was abruptly halted by something I couldn't see. The TACC did red-flash and beep... but it also stopped, with me touching nothing.
     
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  8. ThirdMartini

    ThirdMartini Member

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    Had my first TAC + emergency braking encounter today. TAC ON and set to 75, following traffic in front of me on I25 south coming into Denver. Traffic begins slowing down to around 40 MPH.. TAC brings speed down to match , I put my foot on the break pedal ( just incase, since I don't trust it yet and have no clue why traffic is slowing ) when the car in front SLAMMED on the brakes. Before I could even react the Emergency Stop kicks in on full with AEBS rattling. Stopped my car 3-4 car lengths from the one in front. Impressive.

    PS. Seriously, who lets their dog out of their car on the side of the highway. I don't think he made it :mad:
     
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  9. Cyclone

    Cyclone Active Member

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    Sorry to hear about the dog, but glad the Tesla's safety features kept you well behind harms way.
     
  10. brianman

    brianman Burrito Founder

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    TACC behaved perfectly.
     
  11. billarnett

    billarnett Member

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    That's interesting! I thought the emergency braking was supposed to trigger only if it was 100% sure that a collision was going to happen. But in your case it was apparently no where near a certain collision. Are you really sure your foot didn't touch the pedal?
     
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  12. Danal

    Danal electricmotorglider.com

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    I was driving 6.2 at 50 to 55MPH on a two lane blacktop, TACC locked on car in front of me on setting 3. A pickup jammed his way in between me and the car in front via a side-street turn-in, and then the whole pack was abruptly halted by something I couldn't see. The TACC did red-flash and beep... and it also stopped successfully, about one car length back, with me touching nothing. I am absolutely certain I did NOT touch the brake, as I was verbalizing the TACC actions to my passenger, who was receiving a demo ride. So I toughed it out. Probably bad judgement, but a good data point for this discussion.

    So yeah, I'm beginning to see the "...inevitable collision..." phrase as a pure liability defense, and not at all as a description of system behavior.
     
  13. ThirdMartini

    ThirdMartini Member

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    I suppose its possible as it all happened so quickly, but I could swear the audible alarm went off and the car started braking before my foot touched the pedal. I was tempting fate a bit by being curious how far TAC would bring the speed down ( with foot over the brake just in case) as I was assuming we're just coming into a slow jam, when the car in front slammed the brakes.
     
  14. ecarfan

    ecarfan Well-Known Member

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    Reading @Thirdmartini's post it appears to me that the car clearly decided a collision was a high probability event and took the appropriate action. I do not understand why you think the situation described was "no where near a certain collision". The car in front "SLAMMED" on the brakes. The car reacted far more quickly than a human driver could have reacted. The car can make decisions and take action in a matter of milliseconds. People cannot do that.
     
  15. andydoty

    andydoty Member

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    I think it's important to note that we should probably separate two aspects of the comments above. TACC and collision avoidance. It is not required that you have TACC enabled for collision avoidance to react. I have found TACC to be pretty solid. It even slowed down due to a cyclist in the right most part of the lane. Collision avoidance is still a little bit of an enigma. It saw a car that apparently stopped at a stop sign on a road that was T'd onto the road I was traveling. Apparently they started to edge forward and Sparky reacted by beeping and slowing down even though they really were not that close to me (I think). The second time I was distracted and it thought I was doing to rear end the car in front of me and slowed (or I may have). I will say that TACC is also pretty good at determining what's going on with cars that "cut in front" of it although it is a bit hair raising when cars come to an abrupt stop on the highway doing 70. Even still, I have my put right near the brake. This is going to take some getting used to...
     
  16. ThirdMartini

    ThirdMartini Member

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    Right, what I believe I observed was TACC first slowing with the traffic... then the collision avoidance kicking in when the car in front locked up their brakes. Unless TACC can kick in 100% brake (enough for ABS to kick on). I was pleasantly surprised it all worked so seamlessly in my particular case. Oddly enough I'm still weary of relying on it ... brings up interesting human problems when the cars become more autonomous. ( IE: back seat driving ... or maybe thats a good thing )
     
  17. billarnett

    billarnett Member

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    Did you happen to note the make/model of the car in front of you? If he locked his brakes then it's not so surprising that you were able to stop so far behind him with your ABS. What I'm reacting to is the discrepancy between "inevitable collision" and your experience. It sure would be nice to see the vehicle logs...
     
  18. green1

    green1 Active Member

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    I think I saw in one of the screen shots posted that collision avoidance also has a 3 level setting somewhere which could affect how early it brakes in an "imminent collision" situation.

    As a side note, a better choice for testers than "let's see if collision avoidance will work" in a real live situation would be instead to go to a large parking lot or something and place a cardboard box (possibly with tinfoil to ensure the radar sees it (though i think collision avoidance is camera based)) and try hitting that, if collision avoidance fails, no harm will be done. (I've seen this strategy used by labs and vehicle testers and it's a much safer plan)
     
  19. billarnett

    billarnett Member

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    That setting is for the collision WARNING not the emergency braking.
     
  20. green1

    green1 Active Member

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    Are the two not linked? Would seem logical.
     

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