Model Y

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Cool & Scary Experience & a question

We've had the Y since the beginning of the year and, due to the pandemic, have not been driving much, mostly around town. Today, wife was driving and we were on an interstate highway for a few miles. Wife sees a car closing in super fast behind us, looking almost certain to rear-end our car. As she's verbalizing "oh my oh my oh my" I felt a sudden acceleration. Sudden enough and forceful enough to pin my head back against the seat. It's a measly LR, without any acceleration boost, but I tell ya, it scares me to floor it, as thrilling as that feels. Now, I was sure wife had accelerated to put some space between us and the maniac behind us, and I wanted to commend her for quick thinking and action. Turns out, she didn't do it, and she had as much of a surprise whip from the unexpected acceleration as I had. Thankfully, there was no crash, and the maniac exited the highway soon after.

But I'm wondering, did the Y sense the car behind us closing in real fast and accelerate on its own to avoid a rear-ender? The acceleration did not last long, perhaps two or three seconds--not sure if this is accurate--since there was a car in front of us. We were in such shock and awe that it occurred much later to save the dashcam video.

We have FSD, but we do not use it. At the time this happened, the Y had warned that autopilot had been disabled. Since wife never engaged it, it's a puzzlement as to why that message popped up.

So, question: is this (self-accelerating to avoid being rear-ended) a known safety feature?

Comments

  • I'll be the first to jump in. I wonder if your wife instinctively just reacted by accelerating? That would be my guess, especially since you had neither FSD or Autopilot engaged.
  • 1. "At the time this happened, the Y had warned that autopilot had been disabled. Since wife never engaged it, it's a puzzlement as to why that message popped up." - This is a bug. I'm experiencing it frequently. It's probably unrelated.

    2. My assumption is that collision avoidance is turned on, and even if you weren't in autopilot or cruise control that the car did it's job.
  • @pianewman: that was my initial thought, but. she admitted she had frozen momentarily, and she is sure she did not floor the accelerator. I think she would know if in fact her body reflexively took action?

    @GuyManDood: Thanks about confirming the bug regarding the autopilot disabled message. As for collision avoidance assist, just read the manual again, and the manual lists three features: forward collision warning, automatic emergency braking, and obstacle-aware acceleration. All three seem focused on forward collision, not being collided in the rear?
  • just curious, if there was no one in front of your car causing your wife to slow, why was there such a rapid closing speed, was your wife driving slowly or the other driver speeding?
  • > @hodori said:
    > @pianewman: that was my initial thought, but. she admitted she had frozen momentarily, and she is sure she did not floor the accelerator. I think she would know if in fact her body reflexively took action?
    >
    > @GuyManDood: Thanks about confirming the bug regarding the autopilot disabled message. As for collision avoidance assist, just read the manual again, and the manual lists three features: forward collision warning, automatic emergency braking, and obstacle-aware acceleration. All three seem focused on forward collision, not being collided in the rear?

    "Obstacle-aware acceleration"? Cannot see how this is part of forward collision avoidance. Sounds like the cars did it's job which would be a very nice feature.
  • > @Mortskiv said:
    > "Obstacle-aware acceleration"? Cannot see how this is part of forward collision avoidance. Sounds like the cars did it's job which would be a very nice feature.

    Having read the text, I'm wondering if "Obstacle-Aware DEceleration" wouldn't have been more accurate description. Here's a direct copy from the manual:

    "Obstacle-Aware Acceleration - reduces acceleration if Model Y detects an object in its immediate driving path "
  • > @lbowroom said:
    > just curious, if there was no one in front of your car causing your wife to slow, why was there such a rapid closing speed, was your wife driving slowly or the other driver speeding?

    The other driver was speeding like a MANIAC.
  • So your car accelerated to match the maniac speed and then you maintained the speed? How many lanes? Did the maniac eventually go around you?
  • > @lbowroom said:
    > So your car accelerated to match the maniac speed and then you maintained the speed? How many lanes? Did the maniac eventually go around you?

    The second paragraph of the original post has details you seem to have missed.
  • Radar is located in front of MY and provides range and rate of closing data. Rear camera range is 250Meters. Range of sensors is 8Meters and are activated when driving at less than 5MPH. Per the manual for MY: "Obstacle-Aware Acceleration is designed to reduce the severity of an impact. It is not designed to avoid a collision."

    I think you owe your wife thanks for some excellent instinctive driving.
  • ^^^This. I would file this in an "Intended Acceleration" file, which fortunately has a happy ending. (The "unintended acceleration" issue of the mid-80s, which was claimed against several manufacturers, was overwhelmingly ruled as 'driver error', sadly ending in consequences that were deadly.)
  • I remember seeing a YouTube video of a Model S doing the same thing years ago.

    Model S driver had a vehicle behind that wasn’t paying attention and closing fast on I believe an exit or entrance to a highway. The Model S accelerated on its own according to the poster and avoided getting rear ended.
  • https://www.youtube.com/watch?v=KHvLFujWBeg

    One of the most watched tesla videos out there. 25 seconds in shows a tesla accelerating to avoid being rear ended. These were all confirmed to be on autopilot
  • Found the dashcam footage! I remember pressing on the dashcam icon an eternity afterward, but apparently I did it in time and the footage was saved. [First time with dashcam, so this is very exciting! :-)].

    We were in the right most lane, waiting for an opening to move one lane over. The footage shows the speeding car cutting across two lanes (and other cars) in quick succession to get to the right most lane, apparently to exit, and he's flashing his lights. The car behind us was literally at the lane marker in the process of switching lanes and I can see the driver makes a quick correction to avoid a collision.

    It does not seem as dramatic as I remember it, but it looks like the other car got within about two car lengths, slowed down, and sped up again and got within about a car length and slowed down second time. And that's when I can see the Y speeding up.

    So the other car was driving like a maniac but appears to have been in control enough to have avoided a collision, if it came to that.

    Wife is sure that she did not accelerate, so I'll leave it at that. Sure would like to know if this is a documented and expected behavior of the car. And read the official word/description, if there is one. If it is indeed confirmed feature/behavior of the car, is it part of the standard package?
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