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Potential AEB misstep. I may have lost confidence.

Discussion in 'Model S' started by CHG-ON, Apr 13, 2016.

  1. CHG-ON

    CHG-ON Still in love after all these miles

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    I keep my collision warning (AKA Automatic Emergency Braking-AEB) at max just to be conservative. So I tend to get a fair amount of false alarms. I don't mind it because I want to be safe. I tend to get them when the person in front of me is slowing for a light or a car and I am just about to tap the brakes. I am almost always in regen, I think.

    Beep beep beep! And I think, I know, I know!

    I don't tailgate at all (anymore!).

    Today I was travelling down a good slope, with regen. The car in front of me slowed much more than I expected for somebody turning. The sun was in my eyes and I suddenly realized that he was stopping for a turn, not just slowing. I had just instinctively put my foot on the brake to slow more before realizing this was happening. I then slammed them on, locked the brakes for perhaps 2 ft and all was fine, fortunately. But normally the AEB goes crazy when I am farther away. I wonder if AEB does not work when the foot is on the brake. That concerns me. A light braking is much different than a firm braking. I would think that AEB would be active and vigilant regardless of whether I am braking or not and would be ready to increase braking to avoid the accident even if I were braking. The car was unfazed.

    And then, to add insult, one minute later I was slowing on regen for a stop with a car in front of me the damn thing went off when I had more than enough room for a slow and steady stop.

    Oddly, just this morning I was thinking that it was confidence inspiring to have the car be so sensitive to the approach rate to a car in front of me. Now I have lost that. Fortunately, I live in an area where this is actually the first time that I have had to slam my brakes on in my MS in 19 months. They worked like a charm. Not even a shudder.

    I'll share this ServiceNA.
     
    • Informative x 1
  2. liuping

    liuping Active Member

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    AEB is likely assuming if you have you foot on the brake, you are already aware of the situation and want to control the braking yourself. I think that is the right thing to do.
     
  3. Todd Burch

    Todd Burch Electron Pilot

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    Someone can confirm because I may be remembering this incorrectly, but I'm fairly certain that the manual/release notes (when it came out) indicate that indeed, AEB disengages when you are applying the brakes manually. It figures that if you have taken over braking, that you have control over the situation.

    There is probably good reason for this, and is probably consistent with how other AEB systems work. Can anyone confirm if other automaker's systems work this way?

    Edit: liuping beat me to the punch.
     
  4. Muzzman1

    Muzzman1 Member

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    I remember reading in the manual if you make an evasive turning maneuver or use the brakes it will deactivate AEB

    but don't quote me on that.
     
  5. CHG-ON

    CHG-ON Still in love after all these miles

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    Thanks guys! It's been quite some time since I read through the manual. Nothing happend, so I am happy. Since I have not really thought about whether it should or should not still be active, I really don't know what I think about it. With the sun in my eyes, it may have been helpful. But I can also see it causing more problems. Now I need to learn the logic behind the design. Another fun thing to hunt down!
     
  6. RogerHScott

    RogerHScott Active Member

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    Someone reported in another thread that AEB had kicked in surprisingly, braking very hard in a situation the driver felt they had under control. Anyone who experiences this should be sure to tell Tesla immediately so that if there really is a problem in the recent firmware update they can get on it.
     
    • Helpful x 1
  7. zswilliams

    zswilliams Member

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    It should be pointed out, that AEB is not the same as Collision Warning.

    AEB will engage at some point if a crash in imminent.

    The Warning will happen prior to that at a setting sensitivity of your choosing.

    Changing the warning sensitivity in no way affects AEB timing.
     
    • Informative x 2
  8. AWDtsla

    AWDtsla Active Member

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    I had both conditions active at the same time. Without comprehensive release notes, behaviors you thought were consistent change in software updates, making everyone wrong about how they think the car works. There's no way to know at this point unless someone wants to repeatedly try to convince their car they're about to crash.
     
  9. Spidy

    Spidy Member

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    This seems counter intuitive. Using the correct amount of braking force is a very common error, so not something I would always assume the driver to get right. It's something they even train in driving school in Germany "Gefahrenbremsung". I actually got it wrong twice first because you really have to stomp your foot on the brakes to get 100%.

    Mercedes for example will therefore even adjust the braking if it feels you didn't apply the right amount.
     

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