How often do you experience phantom braking

[Marius A]

I think most people on this forum has experienced phantom braking. Some think it's no problem, others think it's a crime against humanity.
Personally I think it's such an awful experience that I don't use TACC or AP any more. Every once in a while I use it while I open a bottle or put on my sunglasses or similar, and I'll leave it on to see if I experience phantom braking again. It almost always happens (example video below).
So, how often you do experience it?

Feel free to comment below. I haven't stated my opinion on how bad it is, but feel free to tell me I'm a <something derogatory> who can't appreciate the <fanboy statement>

 

[Mo City]

Haven't had any issues with overpasses in quite some time but they must get these GPS speed limit errors fixed ASAP. No doubt about it. 65-50-65-50-65-50-65-50-65 in a 1 mile stretch on Highway 288 southbound in Houston Texas. Ridiculous!

 

[Knightshade]

I've got nearly 20k miles of driving, probably 90% on autopilot.

The car has basically never "phantom" braked- there was always a reason, even if occasionally it was an incorrect decision (and even then rarely) like thinking someone's about to come into my lane when they're not.


And when it does- it's nowhere near the "neck snapping nightmare" folks make it out to be... in a previous thread someone actually measured typical AP braking with an accelerator and it was only about 0.2g- or roughly what regen gets you with no mechanical braking.


FWIW virtually all that driving was using it in places it's intended to be used (controlled access freeways).


I will say since they added the "slow for adjacent lanes being slow" but I notice it slowing (again not violently) a bit more often in a few more situations I probably wouldn't slow down- but nothing dangerous or to where I'd prefer to be driving entirely manually.

 

[israndy]

It seems to only happen to me at specific locations and under specific lighting conditions. So implying that it's a percent of the time isn't a realistic poll. If I drive exclusively back from the dog park after work then 100% of the time. Now that all dog parks are closed for CV abatement it's 0% of the time.

There are other locations that I used to hit pretty regularly. I try to disengage the AP when this happens, I understand that's a good step in training the AP so it will map these areas out as they did for overpasses. Hopefully when we all go back to normal life some of these areas will have been mapped and we won't experience the issue.

I am still more affected by the cars that don't pull 100% off the roadway when they turn off. The car will always slow to a stop or at least a crawl to get past them. This isn't anything the car learned from me, wish I knew who's driving style they are apeing. So annoying.

 

[Marius A]

I

I've got nearly 20k miles of driving, probably 90% on autopilot.

The car has basically never "phantom" braked- there was always a reason, even if occasionally it was an incorrect decision (and even then rarely) like thinking someone's about to come into my lane when they're not.


And when it does- it's nowhere near the "neck snapping nightmare" folks make it out to be... in a previous thread someone actually measured typical AP braking with an accelerator and it was only about 0.2g- or roughly what regen gets you with no mechanical braking.


FWIW virtually all that driving was using it in places it's intended to be used (controlled access freeways).


I will say since they added the "slow for adjacent lanes being slow" but I notice it slowing (again not violently) a bit more often in a few more situations I probably wouldn't slow down- but nothing dangerous or to where I'd prefer to be driving entirely manually.

I've put in approximately 14k miles in my two TM3s, and they are equally bad at phantom braking.
Measuring from that video, provided you believe me, it braked from 120 to 90 in between 1-2 seconds. That's between 0.42 and 0.85 G, so quite harder than normal regen.
Not sure if the highway in the video differs much from normal highways in the US?

 

[boiler81]

I use Autopilot on two lane highways, and I've noticed an increase in phantom braking over the recent software updates (last 6 months?).
I believe my incidences are triggered by oncoming vehicles, which upon cresting rises in the road, momentarily fools autopilot into thinking they are on a collision course. I guess Autopilot's being very defensive, but it didn't behave this way in 2018 or the first three quarters of 2019.

 

[TX_M3P+]

I've had my car for almost 2 months now and I've used AP ~5 times and TACC I use quite a bit. My worst experience happened while I was doing 70 on a freeway with an upper and lower deck split. I took the 2 lane lower deck and was coming up on a slower driver in the right lane. I signaled to get into the left lane and the car made the lane change then slammed on the brakes. I went from 70 to 50 very quickly, and having moved into the left (faster) lane, the car slammed on the breaks in front of faster moving traffic. I honestly was so jarred that I couldn't think of what to do in that moment. I disabled AP and slammed the accelerator to quickly get back up to speed but not before multiple car behind me had to slam on their brakes to avoid rear ending me. My heart was pounding and my hands were sweating and it took me a few weeks to even think about turning on AP again. I've tried it a few more times since and have not experienced it again. I have experienced similar things using TACC but at much slower speeds. Based on what I have observed, I think when the Tesla locks on to the car in front of it, if that car changes lanes or if the Tesla changes lanes, it seem to remain locked onto that car and is very hesitant to pass at the set speed. Once it does finally pass that car, at a reduced speed, it will then return to the set speed and resume normally.

 

[holmgang]

too damn much.

i only use TACC now in (1) ultra light traffic, where theres low likelihood of someone behind me (2) gridlock traffic where speed is slow.

in normal traffic, its too unreliable. not to mention is the poor speed mapping as wlel

 

[RayK]

Early on, and by that I mean late 2018 to mid 2019, I had a couple of instances where phantom braking occurred. However, since then, I can't remember a time when it's happened. It was jarring enough that I'm still hovering my right foot over the accelerator, rather than the brake, when I'm running TACC or NoA. The times that it happened were the usual - approaching an overpass.

 

[Bobbins]

Pretty well every journey that I use the TACC at some point I get phantom breaking. Today in a 50mph limit, single lane each way and using TACC because of multiple speed cameras on the route, approaching a left hand 45 deg bend (remember we drive on the left in the UK) a large goods vehicle came round the bend in the opposite direction. Absolutely no danger situation but the system sensed the oncoming vehicle was dead ahead and didn't allow for the bend, so abruptly reduced my speed by 10+ mph. The system simply isn't good enough for general release.

 

[Kevy Baby]

Pretty well every journey that I use the TACC at some point I get phantom breaking. Today in a 50mph limit, single lane each way and using TACC because of multiple speed cameras on the route, approaching a left hand 45 deg bend (remember we drive on the left in the UK)...
The system simply isn't good enough for general release.

You have described a situation where you shouldn't be using AP, so this example is invalid.

 

[Kevy Baby]

13,000 miles, 90%+ on AP. Yes, I've had a few phantom incidents, a couple of which were pretty hard. But most were at most just minor slow-downs.

AP works pretty damned good.

 

[ma2k5]

I’ve had my M3 for less than a week and I’d say it’s very frequent.

 

[Bobbins]

You have described a situation where you shouldn't be using AP, so this example is invalid.

No, this example is very valid .... Tesla's goal with the Autopilot/TACC is to develop full self drive cars, it's not viable to limit where the TACC is used.

 

[Xambler]

3 phantom breaks on recent 1400 mile round trip. 2 when passing trucks (one flatbed semi with flapping tarp over cargo, one an enormous dump truck), the other just in normal Atlanta traffic at night...was just momentary but disconcerting. Next update about 3 weeks ago seemed more stable and drove return 700 mile leg about 95% on navigate by AP with no problems. .6 release a few days ago seems to kick out of AP on our city roads in Florida a LOT more often, though. That is with stop at traffic lights activated.

 

[S4WRXTTCS]

In my experience it happens 2-3 times every 200 miles on a trip.

The biggest issue I have with phantom braking is there are so many sources of it that it's not always apparent as to what is causing it.

One example shown by the OP is when it mistakenly thinks a truck is going to come into your lane so it slows down. I've had that quite a few times because I5 (mostly what I use) is really owned by semi's between Seattle and Portland. It's absolutely ridiculous how much semi-traffic goes between the two cities. It's basically the semi-truck torture test.

The second source of phantom braking is speed limit changes. Thankfully this doesn't impact TACC as far as I can tell, and only impacts AP/NoA.

The third source of phantom braking is false detects like over passes, etc. I haven't really had much issue with this. It might have to do with everywhere I go is heavily traveled by Tesla's.

The fourth source of phantom braking is NoA which can be really annoying especially when it doesn't have good nav information. Like it's basically unusable for me around Tacoma which isn't surprising as it's endless construction. The car will think it needs to exit soon, and tries to slow me down.

The firth source of phantom braking is AEB, but I haven't experienced this in my Tesla. I experienced it once in my Jeep Wrangler, and it just full on slams on the brakes. It did it when I was going down a ramp into a parking garage, and it thought I was going to run into the wall as the ramp just swoops down. So it was understand, but really jarring.

Usually with the Tesla I get the FCW, but the AEB doesn't activate. I get quite a few FCW warning, and half the time I have no idea what it's even warning me about.

Now Tesla has added yet another source of phantom braking with Traffic Light Control. Someone else has a post where they actually had this enabled on the freeway. Suffice to say it didn't go well, and led to all sorts of phantom braking when the freeway went over surface streets. I'm going to disable this before using TACC/AP on the freeway.

 

[toolman335]

For me it has only happened when my car is filthy. I know it sounds simple and dumb, but the car has to see clearly.
I saw on another thread that some people wipe down their cameras before driving every day as a pre-trip inspection. Makes sense. You want perfect vision.

 

[Marius A]

For me it has only happened when my car is filthy. I know it sounds simple and dumb, but the car has to see clearly.
I saw on another thread that some people wipe down their cameras before driving every day as a pre-trip inspection. Makes sense. You want perfect vision.

Totally understand clean car, but wiping down your cameras every time you drive like a pensioner with an expensive Mercedes is silly.
The car will get dirty while driving, it should be able to handle regular buildup. Not sure if it makes a difference on my car, I haven't tried washing it and immediately testing TACC/AP.

 

[XLR82XS]

It happened a few times for me months ago but not anymore with the latest software version.

 

[Pilot1226]

Haven't had any issues with overpasses in quite some time but they must get these GPS speed limit errors fixed ASAP. No doubt about it. 65-50-65-50-65-50-65-50-65 in a 1 mile stretch on Highway 288 southbound in Houston Texas. Ridiculous!

You're submitting the bug reports, right? Like pushing the talk button and saying "report bug, phantom braking"? Or is there another way to register it...