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PSA: CAREFUL--Autopilot sudden braking


Mar 9, 2017
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.


Jan 9, 2017
Palo Alto
Yeah, I have noticed this too - it takes you by surprise the first time it happens. Now when I see a similar situation, I hover my foot over accelerator in case I need to press it to maintain speed.
  • Funny
Reactions: jimmyjohn


Nov 9, 2017
San Diego
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.


Feb 7, 2018
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.
  • Informative
Reactions: chibi_kurochan


Dec 28, 2016
It has happened to me both in the MS and M3. Usually for me it is when a car is pulling out of my lane and moving into a turn lane and slowing down. It is pretty consistent. I haven't had a problem with overpasses in many months.
  • Like
Reactions: vernontwg


Feb 17, 2018
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.
  • Like
Reactions: EkBuZ
Jan 20, 2017
San Jose, CA
Happened to our Model 3 several times too. Did not realize until this thread that it was potentially due to the overpass.
The most recent one was yesterday driving on 880S under Coleman overpass. At first i thought it was due to the dip on the road and ultrasonic/radar thought it about to crash to the "road".

Google Maps
Jan 20, 2017
San Jose, CA
Should add a poll, this looks like a recurring large scale bug.

FYI, i'm on 2018.14.13
Everyone report this to Tesla Roadside right away or leave the Voice Note using the car's voice command.


Supporting 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....
  • Helpful
Reactions: RBowen and TaoJones

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