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phantom braking. Are you still experiencing it with latest software update?

Are you still experiencing it with latest software update

  • yes

    Votes: 88 72.1%
  • no

    Votes: 34 27.9%

  • Total voters
    122

pipestem

post-newbie
Nov 29, 2018
253
230
Center of the Universe
Most of my experience with PB is more than just slowing. When I’m in heavy traffic and the car “slows” from 65 to 45 unexpectedly for no apparent reason and quickly enough that it creates a possible rear end collision situation, I call that phantom. No to mention unnerving. So many tailgaters out there. Even when I’m expecting it b/c it’s in the same location as it’s happened before, it still startles me. The rate of deceleration is more than just slowing, definitely is braking. Now I just flip TAAC off just before I get to those 2 spots. With the exception of those 2 locations which BTW are in construction zones, PB has almost become a non-issue.

I only notice PB when using auto-steering,, not just tacc. Darkened overpasses are the worst. Probably only once a month or twice a month right now. It's hard to explain - yeah the car is great it just tries to kill me sometimes.
 

TLLMRRJ

Active Member
Dec 19, 2019
2,017
2,002
Houston
I don't know what else they can do. Unquestioningly hugging the left would be dangerous.

What it's doing right now is dangerous, especially with offs ramp and the car freaking out and jolting when it gets to the fork in the off ramp.

If the car can see the lane lines far out (if it can't then that's a bad sign), why would it be dangerous to hug the left lane line and be programmed to know that there's no situation where lanes are 30ft wide and the car should be perfectly centered in a 30ft wide lane anyway?

I don't know what they're thinking.
 
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jw934

Supporting Member
Supporting Member
Jul 23, 2018
281
5,422
Canada
updated to 2021.12.25.6
Went for a drive today on a stretch of motorway I regularly drive
which I quite often engage AP/NoA without any phantom breaking

Today 2 occurrences of PB both looked to be the same scenario
Passing a car which was on my left, in the left lane
No bridges or overhead signs in front. in both instances the car I was passing was behaving normally
not drifting across the lane not signaling. I was traveling on the right in the right hand lane
My car suddenly decided to rapidly slow down and stop passing the car on my left
for no reason that I could see. It did this twice once on the way out and again on the return journey
I think it went from 100km/hr to about 70 or so. I did accelerate once I was sure nothing was wrong
I wasn't game enough for science to let the car decide how much it was going to slow down

With AP/NoA engaged I also passed other cars the same way and had other cars pass me
on the same journey without incident

May be its not phantom breaking, maybe it's driver alertness test to make sure your really are paying attention
to keep you on your toes, alert and ready for the unexpected...lol
I wonder about the time of day and the direction you were travelling at the moment of the PB as the shadow from the two cars on the left could have casted a shadow on your lane. This could be the same effect as passing into the shadow under a bridge or when entering a tunnel.
 

S4WRXTTCS

Well-Known Member
May 3, 2015
5,631
6,405
Snohomish, WA
On the weekend I drove to the Oregon coast through Portland, and I only experienced around 4-5 phantom braking events

As far as I could tell nearly every single one of them was caused by the maps/navigation indicating the car was on a surface street (or undivided highway). They were temporarily glitches where I saw the set speed change to something way lower than the set speed was. They were all in areas where construction recently occurred or Tacoma (which is perpetual construction).

I didn't get any phantom braking due to semi's phantom braking
I didn't get any "while in a corner next to a semi" phantom braking
I didn't get any Traffic light response phantom braking as I had that turned off
I didn't get any NoA phantom braking as I had that off

For me phantom braking is no longer the worst part of AP.

The worst part of AP the recentering when the right lane loses its lines at merge points. It cannot satisfactorily handle merge points or where a new lane is created by expanding the current lane. It gets confused and then suddenly jolts to one. A normal driver would simply follow the left line or would get over if they were the slow one.

Auto-lane change continues to be the best part of AP as long as it's not used in certain situations. Things like a vehicle approaching quickly on the left because it won't be quick enough or doing a lane change into a lane next to a semi as it gets confused by where the semi is.
 

greymatter73

Member
Jun 7, 2021
170
214
Elk Grove, California
Had a weird phantom braking incident this morning on my commute. I was going 80mph in the fast lane at 4:00am on a long straightaway with no turns in site. The only cars were in the #2 and #3 lanes. The car in the #2 lane merged into my lane about 200 yards in front of me and my car suddenly slammed on the brakes. Luckily nobody was following close behind me, otherwise that would have been ugly. The only thing I can think of that could have contributed to this was that the car that merged had tail lights out, maybe tricking the Tesla Vision to think it was closer? ¯\_(ツ)_/¯
 

Fernand

Active Member
Mar 22, 2019
1,557
1,566
Northern california
There's a lot of stuff they're changing at the moment. Be awake, be alert, this isn't for sleepy seniors.

My cameras vanished the other day. I reset the screen computer, wiped the lenses and said nice things to it. Nada. No cameras, no auto-anything. After stopping at Costco I was about to drive down to the Tesla SC, put it in reverse, and everything was back to normal. Huh? And it's still slowing down like crazy way before entering exits, and reading incidental speed signage. I can imagine it reading a residential billboard that says "Are you over 65? Check your Medicare coverage" and setting the speed to 65.

BTW, poor Sandy Monro, keen observer that he is was, and he's cool, but he has no idea about software, and he's talking about how his autopilot is good but gets confused "in, what do you call 'em, erh, subdivisions".
 
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RDoc

S85D
Aug 24, 2012
2,753
1,612
Boston North Shore
I don’t think they will ever solve this. My wife’s first new vehicle ever was a 2011 Ford Edge which came with all the bells and whistles including TACC. That had some pretty scary phantom braking incidents on the freeway on a regular basis. It’s 2021 and if the supposed most advanced cars out there today (Tesla) are still doing it on a regular basis then it’s never going to go away.
I have a 2015 Model S with AP1. I don't think I've had more than 5 phantom braking events in the entire time I've owned the car. None in the last year.
 

Knightshade

Well-Known Member
Jul 31, 2017
12,814
19,000
NC
I have a 2015 Model S with AP1. I don't think I've had more than 5 phantom braking events in the entire time I've owned the car. None in the last year.


AP1 "sees" very little compared to AP2+ cars, so it's unsurprising it'd be far more rare for it react to odd situations
 

Occhis

Member
May 26, 2019
237
106
Front Royal, VA
On the weekend I drove to the Oregon coast through Portland, and I only experienced around 4-5 phantom braking events

As far as I could tell nearly every single one of them was caused by the maps/navigation indicating the car was on a surface street (or undivided highway). They were temporarily glitches where I saw the set speed change to something way lower than the set speed was. They were all in areas where construction recently occurred or Tacoma (which is perpetual construction).
How does the maps/nav display that you are on a surface street as opposed to divided highway?
 

Fernand

Active Member
Mar 22, 2019
1,557
1,566
Northern california
I have a spot "on the way home" coming from the Caldecott Tunnel where Westbound highway 24 merges on a hairpin over to East-Southbound highway 13. At times in the past it was a heroic but successful NOA merge. Then it went to hell and now it still cannot complete in NOA.

Then I realized what's happening. It consistently drops out of NOA for no clear reason there, and treats 50 meters of freeway as a surface road. That sort of thing might explain some peoples' repeat slowing/braking anomalies.


HW24West_to_HW13SouthM.jpg
 
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