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Who Does Not Experience Phantom Braking

Fourdoor

Active Member
May 31, 2016
1,219
1,140
United States
I keep reading about problems with phantom braking however in over a year of ownership, and 24,000km I have never experienced it yet. I realize one hears about problems on a forum as opposed to no problems but how wide spread is it. Are there only a hundred vehicles or so that have this problem? Not too many people will post about not having this issue so I figured I would ask.

I have experienced what I call premature automatic braking when the car judges things are too close for comfort in both my Mercedes and Ridgeline though yet not on the Y.

Am I alone here or are there others who have never experienced phantom braking.

Since you have a 2020 I would not expect you to have phantom braking issues (at this time).

My co-worker with a 2020 M3 SR+ had never experienced phantom braking, driving on the same highways that I drive on and didn't know what I was talking about... he thought I was nuts or exaggerating. Then he got FSD Beta (a vision only system) and now he knows what I have been going through.

If you don't drive on two lane highways, or you have a radar equipped car that is still using radar enabled software you will seldom if ever have sever phantom braking problems. If you don't have radar AND drive two lane highways it is infuriating and borderline dangerous if you have someone behind you. I use "speed limit mode" as a poor mans dumb cruise control now. It sucks not being able to change max allowed speed, but for my daily commute this is not a concern... and it sucks a lot less than vision only TACC on a two lane highway.

Keith
 
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mark95476

Active Member
Jun 21, 2020
2,067
1,589
Bay Area CA
I didn't have any phantom braking until I got FSDbeta. The car would let off the throttle sometimes causing it to coast and slow down slightly on some roads. It was consistent and thought it was the nav system getting confused with roads and speed limits on over/underpasses.

Now I get phantom braking occassionally, but I feel like it's getting better with each release. I can sometimes anticipate where it might happen like patchwork roads at night so I can press the throttle to counteract it.
 

Fourdoor

Active Member
May 31, 2016
1,219
1,140
United States
I didn't have any phantom braking until I got FSDbeta. The car would let off the throttle sometimes causing it to coast and slow down slightly on some roads. It was consistent and thought it was the nav system getting confused with roads and speed limits on over/underpasses.

Now I get phantom braking occassionally, but I feel like it's getting better with each release. I can sometimes anticipate where it might happen like patchwork roads at night so I can press the throttle to counteract it.

Good to hear that it is improving. These improvements should eventually filter down to the TACC used with standard non-FSD Auto Pilot.

Keith
 

joebob1234

Member
May 24, 2021
11
12
MN
'21 MY, Vision only and get phantom breaking regularly. It's beyond annoying and I'm now to the point of filing a complaint with the NTSB as it's truly unsafe and Tesla doesn't seem to be doing anything about it in the last 6 months of Vision only.

Just returned from a 7 hour roadtrip. I'd say I had 6 phantom breaking events. Two of which were severe... 80 to 45. Thank god, no one behind me. These where not collision warnings. I don't think it applied the brake, it just completely laid off the acceleration. When doing 80 and you completely lay off the accelerator, it causes quite the breaking event.

These happen both on Autopilot and regular cruise control. Happens on interstates, divided highways, & two lane highways. Some instances were due to a shadow, while others, I have no clue what caused it.

I can't even use regular cruise control that a 20 year old car has without fear of getting scolded by my wife for the phantom breaking.
 

Midnightsun

Member
Nov 29, 2020
632
688
Canada
Since you have a 2020 I would not expect you to have phantom braking issues (at this time).

My co-worker with a 2020 M3 SR+ had never experienced phantom braking, driving on the same highways that I drive on and didn't know what I was talking about... he thought I was nuts or exaggerating. Then he got FSD Beta (a vision only system) and now he knows what I have been going through.

If you don't drive on two lane highways, or you have a radar equipped car that is still using radar enabled software you will seldom if ever have sever phantom braking problems. If you don't have radar AND drive two lane highways it is infuriating and borderline dangerous if you have someone behind you. I use "speed limit mode" as a poor mans dumb cruise control now. It sucks not being able to change max allowed speed, but for my daily commute this is not a concern... and it sucks a lot less than vision only TACC on a two lane highway.

Keith
I do drive on 2,3,4 lane highways and never experienced phantom braking. I keep reading about big trucks. Tons of 53 footers and even b-train trailers around here on our highways yet never an issue so far.
 

Tha_Ape

Member
Jun 15, 2021
357
274
Washington, DC
My 2021 MY (radar) had a couple of events, but fairly infrequent to the point where I cant remember when the last one happened.

I think mine were due to shadows from passing vehicles appearing in my lane which "tricked" the camera into thinking someone was merging into my lane. I remember the 1st one clearly because a car carrier was next to me and the sudden braking freaked me out. That's just my theory... I cant think of any I've had at night which also fits my theory.

I've only put ~3500mi on my car though, would like to hear from some heavy drivers. (Currently on 2021.36.8)
 
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SFNM Jack

Fueled by the Sun…
Aug 31, 2021
177
142
Santa Fe, NM
The fact it is doing it all in the first place means something isn't right.

I have had numerous issues to the point a lot of the time I don't want to use TACC. I have more issues on secondary highways but even have had it on some 4-6 lane interstates as well.

I have had them on sunny, well-lit days, where it mistakes a shadow as a "threat" and applied moderate to intense pressure on the brakes. I have almost been rear ended several times. This is my biggest regret about the car to date. When they took out the radar, I think it made the car a lot worse. I drove demo cars on the same roads, similar conditions that had radar. Never had phantom braking issues. My car, sans radar, I have a lot more.

I signed the little disclaimer saying I was getting the car that had changed from when I ordered it. If I had known how bad it would have been, I likely would have tried to find one that still had radar. The amount of phantom braking from TACC means the cruise control is more stress/hassle than it is worth. On long trips I'll likely have to go to the dumb cruise method with it.
What is the dumb cruise method? Can you just set a normal cruise control in the MY. I only ask because I’ve seen people complaining this should be available…
 

Tha_Ape

Member
Jun 15, 2021
357
274
Washington, DC
What is the dumb cruise method? Can you just set a normal cruise control in the MY. I only ask because I’ve seen people complaining this should be available…
it still uses TACC... meaning if the car thinks someone's coming into your lane (whether real or imagined), it will brake. Some want disable that as it's believed to be the source of many phantom braking events.
 

mrwug

Member
Jul 30, 2021
409
297
Colorado
My personal definition is that I can't understand why the AI decelerated. Only had the car a couple weeks but most of the 800-ish miles I've driven were with either TACC or AP. Zero phantom braking events based on that definition.

That's not to say that there are no braking issues:
  • When passing a vehicle making a left-hand turn, the car will decelerate significantly
  • When a vehicle makes a left turn across my lane
  • Braking when approaching a stopped vehicle (e.g., at a red light) is much more abrupt than I'd like.
For the first two, I prepare to hit the accelerator in case of undesired braking. In the third, I've started disengaging TACC/AP when approaching a stopped vehicle at the point where I want to start decelerating. Not ideal, but tolerable.
 
I do drive on 2,3,4 lane highways and never experienced phantom braking. I keep reading about big trucks. Tons of 53 footers and even b-train trailers around here on our highways yet never an issue so far.
The big truck problem is real. Had mine only little over 2m and about 2k drive, about 60% of the time when passing by a big truck while on TACC, auto pilot or not it will apply moderate to significant (regen) brake, I basically have to anticipate it coming and override it...It's on those wide 4-5 lanes LA area freeway so it's about as optimal of the road condition as one could expect as far as TACC/Auto Pilot goes.

If you look at the screen it kinda gives you a sense of maybe why it does so as the camera/computer seems to have trouble visualizing the spacing of bigger object correctly as it looks like the big truck is running over my lane when it's not, at least based on how it's rendered on the screen. Also it would occasionally show object such as pedestrian on the screen when I'm driving slowly on the quite neighborhood street when there's clearly nothing around me, which could explain certain phantom brake event since the computer "thinks" there's something there. So still a lot of work for vision only to correctly interpret everything the camera sees.
 
In the third, I've started disengaging TACC/AP when approaching a stopped vehicle at the point where I want to start decelerating. Not ideal, but tolerable.
You can try to increase the car following distance which will improve the timing of when TACC starts decelerating. But depending on your driving habit of how early you would start decelerating manually, TACC may still feel like it's braking much closer to the "last minute" as it can. For a gradually stopping traffic, such that you were following the car in front of you and traffic slows down to a stop TACC reacts pretty well.

But if you're going 65+ and see traffic far in front of you come to a complete stop TACC either doesn't see far enough or just doesn't engage in the decelerating until way too late where it would have to slow down pretty abruptly. I drive quite conservatively and I set my following distance to 6 and I can kinda get used to it stopping from a speed of below 50, but from 50+ to a complete stop it still feels rough to me to the point I would rather just deactivate TACC far in advance.
 
I have not experienced phantom braking because I have yet to try autopilot. The risks outweigh any benefits IMO especially driving my family around.
What I did was driving around myself while testing AP a bit at a time at different speed before I even would turn it on with the family (which I started doing now). For certain things such as stop and go traffic it can really reduce stress but it's up to individuals as to whether its worth to use it, but it definitely requires some adjustment to the driver as well.
 
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Prime203

Member
Jul 29, 2021
29
22
SoCal
You can try to increase the car following distance which will improve the timing of when TACC starts decelerating. But depending on your driving habit of how early you would start decelerating manually, TACC may still feel like it's braking much closer to the "last minute" as it can. For a gradually stopping traffic, such that you were following the car in front of you and traffic slows down to a stop TACC reacts pretty well.

But if you're going 65+ and see traffic far in front of you come to a complete stop TACC either doesn't see far enough or just doesn't engage in the decelerating until way too late where it would have to slow down pretty abruptly. I drive quite conservatively and I set my following distance to 6 and I can kinda get used to it stopping from a speed of below 50, but from 50+ to a complete stop it still feels rough to me to the point I would rather just deactivate TACC far in advance.
Similar experience. The late breaking when going at normal speeds on the highway is jarring. I’ve had / driven several cars with levels of automated cruise control and not are so late to begin breaking. My normal driving is slowing down much before coming close to the car ahead of me, so I don’t think it’s a AI learned behavior. Little puzzled that this “advanced” autopilot system does worse in many situation than more basic radar based systems from years prior. My model is a vision only, seems like the radar equipped version fare better.
 

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