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PSA: CAREFUL--Autopilot sudden braking

I know there are other threads about this. But I think it is serious enough flaw in AP, that I think everybody should be careful (Trust me, I am not a short seller. I own 3 Teslas).

Situation: When autopilot is engaged, it somehow sees some shadows/images, and it brakes pretty hard even though no car is in front of you. It does not come to complete stop, but it will go from 65-70 to 45 pretty quickly.

Conditions: Typically for me it has been driving in the dark (evening or early morning) and going under an underpass. I am not sure if others have seen this during the daytime or other conditions.

Please take notice of this and be careful when engaging autopilot. I have already been rear-ended (not related to this issue), but I can see how this bug can create a hazardous situation where somebody behind could rear end you.

I hope Tesla takes note of this and fixes it soon....it can be fairly dangerous. In the meantime, I have taken to driving again without autopilot until the next update.
It just happened to me today when I went under an overpass. The GPS based speed thought I was suddenly off the freeway and on the surface street overpass and said limited autosteer speed to 45. Luckily I had my foot on the accelerator so I could override it but it just jolt me a bit trying to slow down.

This is on 2018.14.13, never had a problem with this on the previous versions.
Interesting, I have now had this happen to me twice. The first time was Friday, on a wide open freeway with no cars around. Hard brake. It was a pretty jarring event. The second time was this morning, and it occurred during heavy traffic when suddenly a gap opened in front of me. Car started to accelerate and then hard brake despite still being well further than my follow distance from the next car.

Not sure what triggered the false positives. Didn't happen to see if my car showed a phantom car on screen. Now that it's happened to me twice, I won't be in a panicked state, and do plan on submitting a bug report over voice command immediately for any future instances.
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I've had it happen a few times as well. It seems like a few of the times it has happened it might have been when a car in front of my car changed lanes, and then at the last second, my model 3 perhaps views the car that is now mostly out of my lane as some sort of obstruction. The car that was changing lanes never tried to re-enter my lane, but this scenario has happened more than once. It's possible some other environmental object (shadow, overpass, etc.) was coming into play, but I can't say for certain.
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Active Member
Supporting Member
Aug 1, 2015
I had this happen recently in my AP1 Model S. there had been a rash of this behavior a year or more ago, after a certain software release. I have not searched for the thread. But as I recall, the understanding then was that Tesla had a database of things like bridges, and the braking meant that the database was incomplete. So folks were told to file a bug report ASAP after the incident so that Tesla could fix the data.

Whether or not that understanding was true, i have no idea. But I went for many months, maybe a year, without seeing any incidents. Very sorry that they are back again....
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