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  • The final cut of TMC Podcast #34 is available now with topics timestamped. We covered Tesla's rollercoaster prices, Toyota pushing junk science, Mike's new Model 3, Optimizing track mode for snow driving, FSD V11 apparently coming by the end of this week, and more. You can watch and check out the chat replay on YouTube.

TACC “vision only” on radar equipped Model 3 … phantom braking getting scary

Yeah… my wife got super annoyed and our biggest fear was that someone might rear end us or we trigger some serious road rage with someone assuming we are check braking them …. Interestingly on my daily driving around DFW metroplex where I do use TACC occasionally I haven’t had many instances (typically multi lane toll roads with separations). But something between rural roads and high speed limits really upsets “vision only”…

I think it's lack of other cars, and lack of a divided highway. Also undulations in elevation, more common in rural roads than large concrete highways, confuse the vision when the vanishing point vanishes and it can't continue the lane and road lines far enough ahead. It knows there are potentially oncoming cars (no division) and so freaks out and thinks there might be a hidden one right about to pounce over the hill.

It works well in large cities with traffic and straight flat multi-lane highways, where Elon drives, so it was considered good enough.

I favor an "Autosteer without TACC" mode, so the human does the accelerator, and the computer does the steering. There isn't very much phantom swerving.

It's possible this can be done 'manually' by setting a very low speed limit and then overriding it with the foot.
 

texas_star_TM3

Active Member
Oct 28, 2019
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Texas
I think it's lack of other cars, and lack of a divided highway. Also undulations in elevation, more common in rural roads than large concrete highways, confuse the vision when the vanishing point vanishes and it can't continue the lane and road lines far enough ahead. It knows there are potentially oncoming cars (no division) and so freaks out and thinks there might be a hidden one right about to pounce over the hill.

It works well in large cities with traffic and straight flat multi-lane highways, where Elon drives, so it was considered good enough.

I favor an "Autosteer without TACC" mode, so the human does the accelerator, and the computer does the steering. There isn't very much phantom swerving.

It's possible this can be done 'manually' by setting a very low speed limit and then overriding it with the foot.
Or maybe just use radar like literally most other OEMs use for their TACC….
 
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I'm new to Tesla so I can't comment on radar verses vision AP. I can say when I picked up my car in June I was excited for AP, but had several early phantom braking experiences on major CA freeways that shied me away from using it for months. Driving 70 with absolutely no one near me and the car sounding alarms while simultaneously slamming on the brakes. Not fun. Over the course of several weeks after a couple similar experiences I gave up on AP. My Mustang MachE will only do this (hard braking without reason) when a posted speed limit is different than what the car software is programmed to follow (and after reporting the incident I have not had an issue since so Ford must have gotten it corrected).

Only recently many months later on a 5 hour drive to SoCal did I get the courage up to try AP again. While I had some minor braking incidents (meaning a 5-10 mph change for no reason I could see, and not harsh) AP worked great and I was both relieved and happy with the system as the drive down 99 is just a straight borefest so perfect for AP.

I was surprised to see (or maybe not) that Tesla is now removing ultra sonic sensors and going Vision only. I have to question this decision as Vision based AP doesn't seem as reliable as radar and still needs a slot of work. Tesla Is Now Removing Ultrasonic Sensors In Move To Vision Only

More cost cutting at the expense of usability and reliability? Time will tell.
 
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Mikecm1

Mike
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Oct 17, 2020
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I'm new to Tesla so I can't comment on radar verses vision AP. I can say when I picked up my car in June I was excited for AP, but had several early phantom braking experiences on major CA freeways that shied me away from using it for months. Driving 70 with absolutely no one near me and the car sounding alarms while simultaneously slamming on the brakes. Not fun. Over the course of several weeks after a couple similar experiences I gave up on AP. My Mustang MachE will only do this (hard braking without reason) when a posted speed limit is different than what the car software is programmed to follow (and after reporting the incident I have not had an issue since so Ford must have gotten it corrected).

Only recently many months later on a 5 hour drive to SoCal did I get the courage up to try AP again. While I had some minor braking incidents (meaning a 5-10 mph change for no reason I could see, and not harsh) AP worked great and I was both relieved and happy with the system as the drive down 99 is just a straight borefest so perfect for AP.

I was surprised to see (or maybe not) that Tesla is now removing ultra sonic sensors and going Vision only. I have to question this decision as Vision based AP doesn't seem as reliable as radar and still needs a slot of work. Tesla Is Now Removing Ultrasonic Sensors In Move To Vision Only

More cost cutting at the expense of usability and reliability? Time will tell.
Probably a part shortage just like the radar units. We all know teslas goal is vision only, but when it wasn’t possible to get radar, Tesla decided to throw the baby out with the bath water and go all in prematurely. They could have simply said “we can’t source radars, cars will be retrofitted when available”, but instead chose to nerf autopilot since vision only wasn’t ready. That was almost two years ago, it’s still not on par.

It’s a damn shame. I’ve had only 2 phantom braking events in 26k miles of driving. My friends vision only model 3 is not even close to as good as mine. It’s crazy.
 
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I just had the situation where the car deliberately slowed to 90km/h while overtaking a semi-trailer due to the spray from the truck. This was not a phantom braking incident but a deliberate failure of radar-less TACC. It displayed an alert message saying that it was reducing Auto Pilot speed due to poor visibility. This is really dangerous since you are concentrating on passing the truck at the time and are relying on cruise control to maintain a constant speed.
 
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texas_star_TM3

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Probably a part shortage just like the radar units. We all know teslas goal is vision only, but when it wasn’t possible to get radar, Tesla decided to throw the baby out with the bath water and go all in prematurely. They could have simply said “we can’t source radars, cars will be retrofitted when available”, but instead chose to nerf autopilot since vision only wasn’t ready. That was almost two years ago, it’s still not on par.

It’s a damn shame. I’ve had only 2 phantom braking events in 26k miles of driving. My friends vision only model 3 is not even close to as good as mine. It’s crazy.
what *really* ticks me off is that they "Deleted" the radar unit from legacy cars which actually had it... just to simplify the software and FORCE everyone onto "vision only". this is the absolute worst way of doing it... at least buyers after a certain time knew that they wouldn't have radar when they ordered the car. I frankly wouldn't be surprised if ultrasonic park sensor vehicles will have their sensors "deleted" as well and be forced onto "vision only" for parking in 1yr or so as well...
 
what *really* ticks me off is that they "Deleted" the radar unit from legacy cars which actually had it... just to simplify the software and FORCE everyone onto "vision only". this is the absolute worst way of doing it... at least buyers after a certain time knew that they wouldn't have radar when they ordered the car. I frankly wouldn't be surprised if ultrasonic park sensor vehicles will have their sensors "deleted" as well and be forced onto "vision only" for parking in 1yr or so as well...
This is one of the 10 reasons I’m putting Tesla way down my list for replacing my aging Model S.
 

texas_star_TM3

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This is one of the 10 reasons I’m putting Tesla way down my list for replacing my aging Model S.
apparently they are saving ~$140 / car by removing the parking sensors... how about making it an optional $500 package when you order the car? This "all or nothing" approach drives me nuts. And don't get me started on forcing the "yoke" on every single Model S / X buyer...
 
apparently they are saving ~$140 / car by removing the parking sensors... how about making it an optional $500 package when you order the car? This "all or nothing" approach drives me nuts. And don't get me started on forcing the "yoke" on every single Model S / X buyer...

Yoke is another reason I’m turned off about Tesla.

Tesla is really not a mature car maker. They have learnt some lessons since 2008, but obviously lack mature managers. The hubris of being the most valued automaker, combined with the thinking that they are on the bleeding edge of technology is leading to some bad decisions.

The only way they learn is when demand starts to soften. Give them 2-3 years.

The competition is doing them a lot favors for being stuck with their own problematic decision making. 😏
 
I was one of those with a looming delivery of my Plaid right as they were switching the headlights over. I was matched with one of the original headlights and posted about my quandary. I wanted the new headlights but did not want to give up the radar. Had quite a few tell me I was crazy, vision was just as good....

I knew better as I had driven quite a few vision only rental 3s but kept getting told I was worrying for nothing.

I ended up waiting on the updated model. I had feeling that if Tesla was building them without Radar, they would eventually deactivate it in older models anyway and I REALLY wanted the headlights.

Not surprised, I have more phantom braking events in my Tesla Plaid each week than I had in 10 years of my previous adaptive cruise control enabled vehicles. I keep hearing how much better it is on the FSD stack, I am skeptical but if so, I REALLY wish they would at least pull over this portion to the regular software line.

I love my Plaid, but agree, this will likely be my last Tesla due to the phantom braking and the lack of Apple Carplay (I actually like the Yoke but would still agree it should have been an OPTION, not the only choice).
 

Biggie

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Aug 6, 2020
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Amarillo, TX
I can understand that, it was really bad, it used to be pretty good, but as they added more stuff that it recognized the braking for no reason got worse and worse.
I can honestly say the the latest FSD beta has made noticeable improvements to that.
When I last drove 281 to Hico it was appalling, but this weekend on the latest release was significantly better.
A bit further north on Hwy51, it was able to drive that road almost like a human, previously it was no where near that.
My arbiter has always been my wife, the latest release is good enough for her, which is an achievement on its own ;)
My wife is also the arbiter. I made that same drive last weekend, and the phantom braking drove her crazy. I was NOT on FSD or using Autopilot - only TACC. The phantom braking got worse when we hit divided highways with less traffic! Go figure! I really wish they would let us select dumb cruise control until they eliminate the false positive dangers.
 
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CharleyBC

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Jun 28, 2019
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negative. no speed limit signs posted when it happened... the main slow down from 78 mph to 55 mph was literally in middle of nowhere...
We've found it to be very sensitive to mirages. Warm conditions and a straight road in daytime and you can have a mirage like a quarter mile ahead, and the car doesn't know what to make of it and jams on the brakes. This is a great feature for terrifying your passengers, if not yourself.
 

aronth5

Long Time Follower
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May 8, 2010
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My wife is also the arbiter. I made that same drive last weekend, and the phantom braking drove her crazy. I was NOT on FSD or using Autopilot - only TACC. The phantom braking got worse when we hit divided highways with less traffic! Go figure! I really wish they would let us select dumb cruise control until they eliminate the false positive dangers.
I've had 1 phantom braking eventin the last 1,000+ miles of highway driving using FSD with .69. Yet I have some phantom braking on city/streets driving.
Go figure indeed! (Model Y)
 

texas_star_TM3

Active Member
Oct 28, 2019
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Texas
We've found it to be very sensitive to mirages. Warm conditions and a straight road in daytime and you can have a mirage like a quarter mile ahead, and the car doesn't know what to make of it and jams on the brakes. This is a great feature for terrifying your passengers, if not yourself.
also a GREAT use case for radar for TACC ... mirages will fool cameras and eyes but *not* radar. the more i think about it ... the 3rd brake event we had was on a straight road and no traffic coming at us and it was quite warm... could very well have been a mirage
 

texas_star_TM3

Active Member
Oct 28, 2019
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Texas
This happens to me on straight rural roads with no lead cars within 200m.

It's very predictable though, so I've learned to turn it off until there are lead cars (in any lane) within about 150m.

Tesla will eventually fix this, probably within 2-3 months.

so "straight rural roads" with no traffic ahead is considered a corner case for the Tesla AP team and not factored in when yanking out radar over a year ago now... good to know...
 
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powertoold

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Oct 10, 2014
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so "straight rural roads" with no traffic ahead is considered a corner case for the Tesla AP team and not factored in when yanking out radar over a year ago now... good to know...

The reason this is happening is because the car is falsely perceiving a stopped vehicle within 150-300m, so it starts to react to this by braking.

The difficulty in fixing this is due to the wide variety of situations where stopping is necessary vs not.

When there is any car ahead within 150m, the vision system is more "grounded" in what's ahead, so there's much less of this phantom braking.

IMO, I prefer this type of vision-only phantom braking over the prior radar-type phantom braking, which was much harder to predict (and more of a gut punching experience).
 

texas_star_TM3

Active Member
Oct 28, 2019
1,454
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Texas
The reason this is happening is because the car is falsely perceiving a stopped vehicle within 150-300m, so it starts to react to this by braking.

The difficulty in fixing this is due to the wide variety of situations where stopping is necessary vs not.

When there is any car ahead within 150m, the vision system is more "grounded" in what's ahead, so there's much less of this phantom braking.

IMO, I prefer this type of vision-only phantom braking over the prior radar-type phantom braking, which was much harder to predict (and more of a gut punching experience).
but radar based phantom braking was MUCH MUCH rarer and usually tied to true corner cases like coming downhill in front of a low hanging bridge etc. Not a wide open straight road.... a good TACC should not need to rely on visually having a car driving in front of you....
 
I'd like to have a dumb cruise control. Where I drive, the speed limit on some highways is only 70 km/h but these highways were recently rebuilt and could easily support cars travelling close to 120. Even police and 18-wheelers travel around 100, so things get dangerous if you don't travel at least 90-ish. When using TACC, sometimes it will randomly overwrite my set speed to 80 (speed limit + 10) and the car will suddenly start braking hard, which is incredibly dangerous given that traffic travels well above that limit and could lead to being rear-ended or road-raged.

I don't want to be second-guessed, especially when the car doesn't know better. Leave these "smart" features as options you can enable on demand, and let me set a speed and stick to it! 😁
 
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