ACC lunging in stop-and-go

Discussion in 'Clarity' started by Tangible, Aug 12, 2018.

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  1. Tangible

    Tangible Active Member

    Driving in heavy traffic in the rain at 5 to 10 mph with the ACC maintaining speed. Follow-distance set to max because of wet conditions. ACC speed set to 40.

    With about three car lengths in front of me, Clarity suddenly accelerates hard, apparently determined to reach set speed despite lead car going at a crawl. I brake manually to avoid collision; don’t know what the car would have done on its own but unwilling to find out.

    This happens three times, so It wasn’t an anomaly. Has anyone else seen this behavior?
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  3. Perhaps this was due to the rain
  4. ryd994

    ryd994 Active Member

    You are lucky, I wasn't.
    I rear-ended into the car in front and totaled it. Too late to realize the ACC lost control. BTW, it wasn't raining and sight was perfect.

    Insurance pays everything, so it's not too bad.

    Lessons learned:
    ACC is not self driving by any mean.
    Hold the wheel and stay alert. It you can't, ACC causes more harm than goods.

    Plus, I should have recorded the sales rep advertising ACC + LKAS as self driving. I didn't trust that, but that constitutes misleading ads for sure
  5. Tangible

    Tangible Active Member

    Certainly ACC is not self driving, but that doesn’t mean it shouldn’t do its job.

    I’ve used ACC in many cars, starting with a 2006 Acura RL. I’ve never seen this problem before. The opposite problem, unnecessary braking, does happen on all ACC systems from time to time. It’s much less dangerous, though it can risk being rear-ended.
  6. Atul Thakkar

    Atul Thakkar Active Member

    In my opinion ACC can not be used in stop and go traffic. It is more for freeway where traffic is moving reasonably. I have seen in ACC that it accelerate and brakes based on set speed.
    NEVER use any cruse control in wet environment
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  8. rodeknyt

    rodeknyt Active Member

    I've found that the ACC in those circumstances works better if you have it set for the minimum distance, rather than the longest distance. It will start accelerating sooner and not leave itself trying to "catch up" with traffic ahead. It also keeps the yahoos in the next lane from cutting in front of you, since there is less room.
  9. Alantn

    Alantn Member

    In the owners manual, page 401 stated that you should not use ACC with LSF:
    • On roads with heavy traffic or while driving in continuous stop and go traffic.
    Page 407 stated the Detection Limitations and page 412 stated "Automatic cancellation" on
    • Bad weather (rain, fog, snow, etc.)
    So basically, Honda warns about what the ACC can do. This is an assisted system and not a "turn on and forget" system. It still relies on you being alert and know the limitation base on road conditions and your driving style.
  10. Tangible

    Tangible Active Member

    I certainly agree about the need to stay alert and focused. I use it in congested driving to avoid the fatigue of continuall switching between the accelerator and brake pedals, not to relinquish responsibility.

    Owners’ manuals are a combination of actual advice and legal butt-covering. It’s sometimes hard to tell one from the other. I see little point in providing a system called Low Speed Follow if it’s not to be used in real world conditions.

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