How to avoid random/phantom braking!

[ShasteWino]

Clearly the issue of hard braking with no warning at freeway speeds has been an issue people complain about for years. It is bad enough that my wife wants me to sell our 2020 Model S ... and in the meantime, no Autopilot usage while she is in the car.

Surely some of you have figured out how to avoid this problem? Can anyone give me some tips about how to anticipate when this is going to happen or recognize the conditions where TACC should be cancelled? I'd really like to use the features of the car without scaring the heck out of my spouse.

 

[EVortex]

My experience is it occurs approximately 500 ft from approaching an upcoming over crossing and facing afternoon sun. Some have said shadows are the cause and others think it’s the over crossing being mistaken as an obstacle. I don’t know, but based on my experience I think sun location does play a part. As far as avoiding phantom braking is concerned, I have found it to be more pronounced shortly after a software upgrade and seems to go away incrementally with more driving experience on a software version. I make sure I am aware of sun position, oncoming over crossings and how long since the last software update. I just prepare to take over control when those conditions are present and avoid the conditions if possible (different time of day, position in traffic lanes, and proximity to other cars).

 

[murphyS90D]

You can override phantom braking by pushing on the accelerator pedal. I have had a shadow from a large tree at the side of the road cause it.

 

[ShasteWino]

It last happened while I was overtaking a large semi-truck. Slammed on the brakes and swerved to the left, even though the truck did not come close to the lane marker or us ... perhaps it was the size that fooled the sensors. I wonder if disabling side collision avoidance would prevent the car from doing that?

 

[EVortex]

It last happened while I was overtaking a large semi-truck. Slammed on the brakes and swerved to the left, even though the truck did not come close to the lane marker or us ... perhaps it was the size that fooled the sensors. I wonder if disabling side collision avoidance would prevent the car from doing that?

That also happened to me once when the morning when the sun was low in the east and I was heading north in the center lane. The shadow of the truck in the right lane was cast into the center lane and had hard phantom braking - immediately took over and accelerated out of it. I have been in similar circumstances since then and no issues. Just as a point of reference, I am currently on 20.12.11.1 with MCU2 FSD and HW3.

 

[Wol747]

>>Clearly the issue of hard braking with no warning at freeway speeds has been an issue people complain about for years. It is bad enough that my wife wants me to sell our 2020 Model S ... and in the meantime, no Autopilot usage while she is in the car.<<

Bingo!
Mrs Wol747 is the same - I'm not allowed to use the autopilot when she's with me. Which is most of the time.

 

[SoCal Buzz]

No AP and Regen on low when my spouse is in the car. She does not appreciate me always testing how car will react to various situations.

 

[Vector2]

Luckily my wife and I aren’t riding together that often or else she’d definitely ask me to turn it off for one particular quirk.....the insane almost down to a stop braking and delayed re-acceleration that occurs when a car in front of you slows down and turns right or left.

 

[S4WRXTTCS]

You really can't stop it.

You can mitigate it by not enabling the traffic light detection and stopping. You can mitigate it by not using NoA. Now some have said TACC does it less than AP, but I'm not sure about that.

In my experience it only happens about 1 or twice every 200 miles. It can be anything from a shadow to a semi it thinks is going to get into its lane. I'm able to butt sense it pretty fast, and correct it. But, not quick enough for a passenger not to notice.

I wish there was a way to tell it to go into a dumb tacc only. Where it didn't try to detect cut-ins, and didn't try to detect stopped cars. Where it simply went off the radar, and used the camera for localization of the radar targets.

My Jeep Wrangler has a very basic adaptive cruise control system, and I haven't seen it false brake yet.

I say to simply use TACC only, and make the spouse deal with the few times it does false brake. I should disclose that I'm single, and it could be that kind of attitude is why I'm single.

 

[f205v]

Do not mitigate phantom brake! Mitigate wife time in the car with you!

 

[SalisburySam]

>>Clearly the issue of hard braking with no warning at freeway speeds has been an issue people complain about for years. It is bad enough that my wife wants me to sell our 2020 Model S ... and in the meantime, no Autopilot usage while she is in the car.<<

Bingo!
Mrs Wol747 is the same - I'm not allowed to use the autopilot when she's with me. Which is most of the time.

Mrs. SalisburySam also. No TACC ever when she’s riding along. I hate TACC evermore each phantom braking event. Been an issue for almost two years now.

 

[DonE]

Mrs. SalisburySam also. No TACC ever when she’s riding along. I hate TACC evermore each phantom braking event. Been an issue for almost two years now.

I have an S and an X, both 2016 models. I report phantom braking issues every time I visit the Service Center. My X has started to give a beep and text warning and making corrective steering maneuvers (It really doesn’t change the steering, but makes small inputs that I feel via the steering wheel.). It does it on the same road a couple of miles from my house with nothing going on. It probably happens 10+ times a week. The Adaptive Cruise on our S seems better than that on our X, which is 6 months newer than the S.

 

[dipper]

I don't understand why Tesla does not have option to turn on dumb cruise control. Aka no TACC.

Most car makers allow that option, which is smart. Not allowing is DUMB.

 

[Bmac]

Interesting posts. My wife also goes bonkers when the car abruptly slams on the brakes. I notice that climbing a hill where the car can't see that far ahead when the hill turns down is also a cause. I don't know why Tesla isn't more interested in solving these issues because, obviously, they will not get to a well-functioning FSD with these things happening. I thought I had understood that some type of code is generated with immediate breaking which I had always assumed would allow development to determine possible causes.

 

[murphyS90D]

Unless you report the date, time, time zone of the incident no one will ever see the error.

 

[Gaz_]

I have another one that is scaring me recently. I have EAP and when pulling back in after passing the truck the car suddenly decides it has to break and swerve back to the faster lane. It looks from the outside like I'm break checking the truck. I can't seem to figure out the cause of this one but one time the truck driver is going to take offence

 

[David29]

Unless you report the date, time, time zone of the incident no one will ever see the error.

Right. I recall that when these events first began some years ago, that was the approach suggested on this forum -- use a bug report to identify the location and circumstances as soon as possible after it happened. As i recall, the belief then was that Tesla would correct the map file. I can recall one railroad bridge where it happened to me, and to the best of my memory it has not happened there again, suggesting that Tesla has done something to avoid it (or maybe I have been lucky).
Then again, this started when there were most likely fewer than 100,000 cars on the road with some form of AP, and now there are more than half a million with several versions of AP in three different vehicles and who knows how many versions of the code and possibly multiple map sets. So whether or not Tesla can keep up is anyone's guess....

 

[ShasteWino]

Unless you report the date, time, time zone of the incident no one will ever see the error.

How and where do you do that?

 

[Mike Robinson]

>>Clearly the issue of hard braking with no warning at freeway speeds has been an issue people complain about for years. It is bad enough that my wife wants me to sell our 2020 Model S ... and in the meantime, no Autopilot usage while she is in the car.<<

Bingo!
Mrs Wol747 is the same - I'm not allowed to use the autopilot when she's with me. Which is most of the time.

Same for me

 

[Battpower]

Based on multiple posts on TMC, bug reports don't leave your vehicle. Some debate, but even when the driver has to intervene and take control from AP and Tesla may get data sent, if they do anything with that data is doubtful, and even more so now that there is the rewrite due that is (hopefully) from a fresh start and using very different image processing.

As far as what can be done about fantom braking, that depends on the (probable) cause. Two common possibilities are spurious indirect radar reflections making the car think there is a high enough liklihood of an object being in front of the car to trigger braking, and the other being incorrect speed limit data or handling of slowing near a supposed hazard especially around on / off ramps / Road junctions.

I haven't found any way of stopping these braking events other than being ready for them! Radar related tend to trigger connected with overhead signs, entering or exiting bridges / tunnels or near large flat surfaces (could be side of a truck). Not sure if shadows (in addition to radar reflections) are also needed to fool the car's sensors but that seems possible too.