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by reureu 916 days ago
I've been driving an M3 since 2020 and have put 40k miles on it, mostly over road trips throughout California and the western half of the US.

Phantom braking has always been a bit of an issue -- when I first got the car, I just wouldn't use cruise control in heavy traffic, but felt ok using it once out of a city. In the past year or so, it's been so bad I'm scared to use it at all, and I've filed multiple complaints with the NHTSA. I'll be driving on I-80 through Nevada or Utah and every ~10 minutes the car will slam on its brakes. This is dry, consistently lit, consistent colors, minimal bridges casting shadows, etc.

I wish there was a way to make my cruise control "dumb"/non-adaptive just to stop the random abrupt braking in the middle of nowhere.

2 comments

That's weird, I've had a Model 3 since 2018 and it definitely used to have some issues with phantom braking, but for the last ~year it seems to be totally fixed (at least for highway driving, still sometimes gets confused on surface roads). Even in the past though I never had anything close to what you're describing where the car slams on the brakes every 10 minutes in good conditions.

Are you running an old software version? You might try bringing it in for service because what you're describing definitely doesn't seem right.

Are most those 40k miles in the last year or so?

> I just wouldn't use cruise control in heavy traffic

Assuming you’re staying in one lane for a bit, AP actually shines in heavy traffic (especially stop and go).

> I'll be driving on I-80 through Nevada or Utah and every ~10 minutes the car will slam on its brakes.

Two points:

1. The update I spoke of was in spring 2022. AP improved a lot with that update for me. Shadows stopped triggering phantom braking. Trucks driving it adjacent opposite lanes on highways stopped triggering phantom braking. It took away the most egregious errors, imho. So if you’re talking about trips mostly before the spring 2022 update, i can believe it. If it’s after spring 2022, then…

2. Nevada can have lots of reflection mirages due to desert heat. Not sure about Utah, but it wouldn’t surprise me if that was the cause there as well (if it happened have the 2022 update).

I have my criticisms of teslas as cars and as a company, but autopilot is not one of them.

> I wish there was a way to make my cruise control "dumb"/non-adaptive just to stop the random abrupt braking in the middle of nowhere.

Agreed. This is one feature I hope that they are forced to make.

My biggest use case of it would be when it’s raining. AP still forces auto wipers when it’s raining, and it often runs too long (when there is no more rain) and/or too fast.

Of course, since I live in CA, rain is rarely an issue.

The absence of regular cruise control in my Model S Plaid is incredibly frustrating on road trips, particularly since Traffic-Aware Cruise Control (TACC) maxes out at 90 MPH - which is the speed limit on at least one U.S. road. Moreover, if the camera can’t see to its satisfaction, TACC’s maximum speed is even lower.

Camera can’t see ≠ I can’t see perfectly well. It’s dangerous to not have cruise control available at speeds that keep you with the flow of traffic.

Also, autopilot having a maximum speed of 85 MPH makes it essentially unusable on many interstates, where the speed limit is 80 MPH and the flow of traffic is 90 MPH.

So dumb.