Phantom Braking misunderstanding

[alexgr]

I had phantom breaking events over several years, but recently, in both Model 3 FSD and Model Y AP, I saw almost no phantom breaking at all.

And now I see this video from Patrick, the Ford Mach-E enthusiast.

When I pointed out that what they see is not phantom breaking, I'v got this from Patrick.
I think we are doomed as humanity to believe any garbage published by news outlets and influencers. I am so disappointed in people now. Am I wrong about this?

 

[fholbert]

I’ve had my share of so called Phantom Breaking too.

If you pay attention to what’s going on around you, you’ll see it isn‘t phantom at all. Something caused the event.

 

[alexgr]

I’ve had my share of so called Phantom Breaking too.

If you pay attention to what’s going on around you, you’ll see it isn‘t phantom at all. Something caused the event.

I often had the car break on highway bridges and when the road goes down and then up again. This problem has been largely fixed for me in the past several months.

That said, I have one spot on one road where Tesla slows down for a stop for absolutely no reason other than maybe thinking there is a stop sign on another road.

 

[fholbert]

I often had the car break on highway bridges and when the road goes down and then up again. This problem has been largely fixed for me in the past several months.

Coming home from work I had a bridge where my car sometimes braked. I realized two things.

1. When I drive I hug the left line.
2. When I went under that bridge the k-rail came out close to the left line to protect the bridge columns.

If I kept the car in the center of the lane it didn’t brake.

 

[mgs333]

Being pedantic but it's braking.

 

[jeewee3000]

Being pedantic but it's braking.

Yeah but if there's a reason for braking (even if the reason is "being uber safe/conservative" it is not "phantom" braking, i.e. braking just because.

I have phantom braking in my 2023 Model Y when it thinks there is a traffic light where there isn't one at all. (It decides based on flawed map data instead of looking out into the real world) THAT's phantom braking.

 

[derotam]

Phantom braking...braking for something that doesn't exist in reality.

 

[BBTX]

While the argument from the Mach-E guy is silly (there clearly is an intentional safety reason Tesla slows down to closer match with nearby lanes, whether you agree with it or not!), I do want to point out that true phantom braking does still exist in FSDb in some scenarios. It's been a long time since I've seen it on a highway drive or even on well-marked/divided city streets. But on narrow two-way neighborhood roads with no center stripe, I still get a ton of it, and it's very reproducable, with no rational explanation (even when the road has no driveways or mailboxes, no traffic or pedestrians in sight from any direction, nothing sticking out near curbs, etc). In a 2-3 mile stretch near my house, even in perfect conditions I get ~5-7 phantom events per drive. They're not hard stops, just random slowdowns (e.g. 35 -> 30, then back up again).

ETA: This has been happening, IIRC, at least since 11.4.x. I don't remember for sure if 11.3.6 had this specific issue for me. 10.69 wasn't doing this on the same road.

 

[legendsk]

Phantom braking...braking for something that doesn't exist in reality.

Yeah, kind of. But it's just semantics. A bird flying over is real. The shadow it creates on the road is real. Neither one is a real threat. Phantom breaking is a very elegant description of the problem. The car is frequently fooled by illusions of a threat that a human would ignore.

I don't think it is a good idea to anthropomorphize the car and try to guess what it is thinking and ascribe motives to it, when in fact it isn't thinking at all, it's just a computer running a program and we have no idea who wrote the program and whether they had a clue about programming or the problems this program needs to solve?

 

[FordMME]

Sounds like what Mach E Vlog reported were not actual instances of "phantom braking" as folks with more Tesla experience use that term. But if what he experienced is not a bug, then it's a really strange "safety feature." That seems to be the more important point, rather than quibbling over terminology.

I have heard, and this could be total BS, that these issues are being caused by Tesla relying solely on an optical system as opposed to incorporating radar? Any truth to that? Seems like the best system would use some of both.

 

[derotam]

Yeah, kind of. But it's just semantics. A bird flying over is real. The shadow it creates on the road is real. Neither one is a real threat. Phantom breaking is a very elegant description of the problem. The car is frequently fooled by illusions of a threat that a human would ignore.

I don't think it is a good idea to anthropomorphize the car and try to guess what it is thinking and ascribe motives to it, when in fact it isn't thinking at all, it's just a computer running a program and we have no idea who wrote the program and whether they had a clue about programming or the problems this program needs to solve?

Lots of argument to be had here, haha. In actuality all the Phantom Braking events can probably be tied to some kind of real input data and it all boils down to incorrect analysis and conclusions in the software. Unfortunately we don't get any insight into the braking events to find out WHY the car slowed down, we are just left with our outward observations of the situation.

Without repetition of event, it is hard for us to analyze what is going on. I would hope that Tesla is actually looking at all slowdown events to mitigate any errant slowdowns with no reasonable cause.

 

[alexgr]

Sounds like what Mach E Vlog reported were not actual instances of "phantom braking" as folks with more Tesla experience use that term. But if what he experienced is not a bug, then it's a really strange "safety feature." That seems to be the more important point, rather than quibbling over terminology.

I have heard, and this could be total BS, that these issues are being caused by Tesla relying solely on an optical system as opposed to incorporating radar? Any truth to that? Seems like the best system would use some of both.

My point was that this is a design feature of Tesla AP, and not an instance of phantom braking. Yes, we may discuss it and many can dislike it, but when it is called phantom braking, then it is will be spread as "Tesla has severe phantom braking problem that other cars don't", which is clearly misinformation. Again, in the past year the phantom braking problem has largely been eliminated on both of my Tesla cars. I don't think the camera-only AP has some inherent unsolvable problem regarding the phantom braking.

 

[AndrewZ]

Being pedantic but it's braking.

Phantom breaking is in the thesaurus next to ghost busting

 

[gtg465x]

My definition of phantom braking based on comments and videos I see:

1) Braking by an autonomous system due to a condition or event that was not perceived by the driver of the vehicle, usually because they were not paying attention to their surroundings.

My ideal definition:

2) Braking by an autonomous system due to a misperception by the system, such as mistaking a shadow for an object.

I think I've only seen definition 2 happen in my own car one time, maybe, or maybe there was something and I just missed it. If I'm paying close attention, I can tie practically every braking event to something that happened, like a speed limit change, a car inching out from a side street too much, a person walking towards the road, another car veering into my lane, or a car crossing the road in front of me (sometimes the car's reaction is a little late and it brakes when it doesn't need to because the crossing car is already clear, but I wouldn't call that a true phantom brake, just a slow reaction).

 

[Stick2it]

We rented a fairly new (Nov.'22 mfr.date) MY in Feb, of '23 In Hawaii for about 1 week (honeymoon). 2 lane roads, with paint -- double yellow in center, white on right. Experienced PB da few times, when there were no other vehicles on the road near us (oncoming or otherwise). I felt that it was dangerous to the point that "if" I had a tailgater, we would have been rear-ended. Anyway, my "cure" for these events was to have foot on the accelerator pedal, and "adjust" when necessary. It became a non-issue after that (for us). But I do agree that is it an issue that Tesla NEEDS TO FIX!!!!

I also recommend reporting the issue on the NHTSA web site. Our voices will be heard there, and with enough people reporting, NHTSA will put pressure on Tesla to fix / recall (even if it comes down to a SW push).

Report a Safety Problem | NHTSA

File a complaint with NHTSA if you experienced a vehicle, tire, car seat or equipment safety problem that could be a safety defect.

www.nhtsa.gov

 

[TresLA]

They’re confusing the phantom braking issue (although much less of an issue than before) with the intentional safety feature of slowing down when driving much faster than traffic in adjacent lanes as indicated by the chevrons on the display. For reference from the “Tesla Model Y manual”:

When moving significantly faster than vehicles in adjacent lanes, Model Y automatically reduces the driving speed. This is especially helpful in heavy traffic situations or when vehicles are constantly merging into different lanes. When Model Y detects other vehicles driving significantly slower, the touchscreen highlights the adjacent lanes with arrows and detected vehicles in gray, and Model Y reduces the driving speed as appropriate. To temporarily override this feature, press the accelerator pedal.

 

[alexgr]

They’re confusing the phantom braking issue (although much less of an issue than before) with the intentional safety feature of slowing down when driving much faster than traffic in adjacent lanes as indicated by the chevrons on the display. For reference from the “Tesla Model Y manual”:

You can see the responses of the MachE vlogger and co. when I pointed out the exactly same issue with classifying this as phantom braking.

 

[alexgr]

I have a feeling in the past couple month Tesla is under a really big and coordinated PR attack. My conspiracy some 2 years ago was that Ford (and GM) intentionally will make not very good non-competitive EVs and then say that no-one wants them, so EVs are dead. It is unfunny to see these days my conspiracy seems to have merits.

 

[JB47394]

They’re confusing the phantom braking issue (although much less of an issue than before) with the intentional safety feature of slowing down when driving much faster than traffic in adjacent lanes as indicated by the chevrons on the display.

That confusion is Tesla's fault. Normal traffic speed adjustments should be smooth. In contrast, emergency speed adjustments can be jerky. Tesla has far too many normal speed adjustments that are jerky, alarming drivers and passengers alike. One of my greatest hopes for V12 is that it can eliminate most of the jerkiness. Both in speed control and in steering.

 

[alexgr]

That confusion is Tesla's fault. Normal traffic speed adjustments should be smooth. In contrast, emergency speed adjustments can be jerky. Tesla has far too many normal speed adjustments that are jerky, alarming drivers and passengers alike. One of my greatest hopes for V12 is that it can eliminate most of the jerkiness. Both in speed control and in steering.

In no way I would think about Tesla slowdown for slow traffic as jerky. It always was very smooth and generally minor on both of my cars. I guess Tesla could have an option to turn off this adjustment, but then the anti-Tesla PR crowd would scream that Tesla allows to drive unsafely.