Hard, random highway breaking on autopilot

[Webeevdrivers]

I'm saying numerous owners have reported that changing the setting significantly reduces phantom braking- and indeed at least one person went and tested this making the same drive repeatedly with various settings and reported the results as setting that to early significantly increasing phantom braking events... (there wasn't as huge a difference between medium and late)

It'd be easy enough to test our yourself of course to see if you observe similar behavior

That was helpful info. Thank you. It doesn’t happen to us often. We will try the late setting and see if it changes anything.

 

[North75]

Some people claim it happens to them many times a day.

Others than that it happens maybe a couple times a year.

And everywhere in between for others.

I'm much more toward the 'maybe a couple times a year' end of that spectrum- and I drive 90%+ of my miles on AP/FSD, mostly on highways/interstates... but YMMV.

FWIW- for years folks have insisted it's really dangerous (because many, like you, they perceive in the moment the braking is much longer and harder than it really is)- but in all those years I've yet to hear of a single actual accident caused by it.

(it's also a problem common to virtually all radar based cruise control systems- last time this came up and someone insisted it was a tesla-specific problem I cited to much WORSE issues with it from a number of other brands that have had actual recalls and lawsuits over it being that bad for em)

I've always wondered how severe it really is. I keep waiting for someone to do some kind of test while filming from a following car to see what it actually looks like to other drivers.
I've had a few phantom braking events here and there, but they haven't discouraged me from using TACC or NOA.
For what it's worth I've never noticed another driver give me a dirty look from a phantom braking event.

 

[fajitamondays]

Yeah, this is no fun when there's a fully loaded semi right behind you at 70 MPH, and AP decides to slams on the brakes out of the blue. I'm lucky I don't have a Peterbilt hood emblem embedded in the rear of my car after one particularly close call.

I went a solid 6+ months where there were no issues with phantom braking. Sometime around 2020.24.6.1, it came back for me.

 

[DrtyJrze]

The braking algorithm overall definitely needs some more work.

It bothers me how fast the Tesla comes up to cars already stopped at a light. It would be nice if it would coast like a normal human would instead of maintaining 50 mph until we’re like 50 feet from the back of the lead car and then decide to slam on the brakes.

 

[Knightshade]

I've always wondered how severe it really is. I keep waiting for someone to do some kind of test while filming from a following car to see what it actually looks like to other drivers.

FWIW one guy did measure it- with an accelerator- and it was about 0.2gs....which is pretty mild.

Or about the same as the amount of braking from regen- ie just take your foot off the accelerator and don't touch the brake at all- that's the amount of "braking" he measured during phantom braking.

Obviously YMMV and it'll brake harder than that for a genuine emergency stop and such.

 

[iwannam3]

I hit the microphone button and say in one breath "bug report unneeded phantom braking" If you pause at all it won't send it.

 

[wedge]

I have this issue too 2020.32.3 version.
It happens under my wife's profile more than mine so might be related. For her like once or twice an hour for long trips. For me maybe once or twice in several hours. No notification of why just slam.
Really wish they could fix it. It will cause accidents.

 

[webbah]

This tends to happen to me with tunnels and certain sunlight and darkness entering the tunnel. I now keep my foot on the throttle, feathered a bit, as if it brakes and you step on the throttle it will release the brake. I've almost been rear ended a few times so am now more prepared with those tunnels. And I also send the bug reports often...

 

[Shelby16]

My Shelby F-150 does this also. I have noticed a direct correlation on my truck and on my Tesla that when there is a Semi next to me or two lanes over, that is when it happens. It has a hard time figuring out if the shadow/height of the truck is actually in your lane or the one next to it. On my Shelby they told me I could change my front grille so the sensor box could better detect shadows, etc. On our Teslas I think it is done by the front cameras and will just take better software development to make it more accurate at calculating long and tall objects next to us when driving.

 

[Dante]

I have on occasion had the phantom breaking, but more recently, I am seeing a transient drop in speed limit from 100km/h to 30 and then back up. Not sure if someone is maliciously changing the speed limit on whatever database tesla uses? Look forward to a functional camera based speed limit detection soon!

 

[Shelby16]

I have on occasion had the phantom breaking, but more recently, I am seeing a transient drop in speed limit from 100km/h to 30 and then back up. Not sure if someone is maliciously changing the speed limit on whatever database tesla uses? Look forward to a functional camera based speed limit detection soon!

Are you experiencing this due to the update Tesla just did that it will see the speed limit sign and it wanting to lower the speed with cruise on? I have noticed this, but mostly with a turn coming up and it gets nervous you are going to drive into a wall or off a cliff.

 

[dfwatt]

Phantom braking does seem significantly improved with firmware 2020. 40.8. On prior firmware anytime a truck or other large vehicle entered the highway while I was on the Middle Lane and we were approaching parallel and almost tangent but not Collision it would slam on the brakes, and not just regen braking either but often times full friction brakes. It got to the point where I basically would cancel the system out in those contexts. It also was brutal in terms of braking for Shadows. Both of those have improved although it's still has trouble distinguishing whether large vehicles are truly in my lane or are clearly in the lane to the right. It does not seem to be as paranoid about large vehicles to the left for some reason.

I have not tried setting the Collision warning system to medium or late. Does somebody have really good empirical data that this makes a difference in Phantom braking episodes? Or is that just anecdotal?

 

[Knightshade]

I have not tried setting the Collision warning system to medium or late. Does somebody have really good empirical data that this makes a difference in Phantom braking episodes? Or is that just anecdotal?

See my post from earlier in the thread-

I'm saying numerous owners have reported that changing the setting significantly reduces phantom braking- and indeed at least one person went and tested this making the same drive repeatedly with various settings and reported the results as setting that to early significantly increasing phantom braking events... (there wasn't as huge a difference between medium and late)

It'd be easy enough to test our yourself of course to see if you observe similar behavior

 

[EV Promoter]

The Phantom Braking threads are several, too many. My suggestions:

1) Brings all the threads in a single new section "Phantom Braking", also to let know Tesla how many users are pissed off by that and are no more using those Beta automations, TAAC and AP. A good place for people in denial.

2) Promote "Feature Request": Adaptivity Disable Option on TAAC, as in most cars.
Just to avoid to drive a car without even a basic Cruise Control as a +20 years old car.
This is usually allowed to have some CC in difficult situations, as intense traffic and harsh meteo that confuses radars and cameras. Everybody does it.

3) Why to attempt "Beta" Level 3 when your Level 2 is bloody faulty due to ambitious choices.

 

[Redbrick]

I'm on 40.8 and get this everyday...it wakes me up..pretty annoying.

 

[Gasaraki]

I rarely have phantom braking issues. However i keep my feet on the accelerator petal just in case I need to hit it and quit it.