Phantom braking

  • SUPPORT THE SITE AND ENJOY A PREMIUM EXPERIENCE!
    Welcome to Tesla Owners Online, four years young! For a low subscription fee, you will receive access to an ad-free version of TOO. We now offer yearly memberships! You can subscribe via this direct link:
    https://teslaownersonline.com/account/upgrades

    SUBSCRIBE TO OUR YOUTUBE CHANNEL!
    Did you know we have a YouTube channel that's all about Tesla? Lots of Tesla information, fun, vlogs, product reviews, and a weekly Tesla Owners Online Podcast as well!

  • It's OK to discuss software issues here but please report bugs to Tesla directly at servicehelpna@teslamotors.com if you want things fixed.

DocScott

Well-known member
TOO Supporting Member
Joined
Mar 6, 2019
Messages
341
Location
Westchester, NY
Tesla Owner
Model 3
Country
Country
Hmm...this thread is making me think: is it possible that some forms of phantom braking are more of a problem for people with EAP or FSD than AP?

In TACC or Autopilot, with the Speed Limit set to Relative and the Offset to 0, the Tesla will adjust your speed to what it perceives to be the posted speed limit (indicated in the upper right of the area of the screen with the car avatar). If you engage TACC or Autopilot while going slower, it will immediately speed up to the perceived limit.
That's not what happens for me--and I have just AP, with the offset set at +2. When I engage TACC, AP just sets the speed to whatever speed I was going. If I tap on the speed limit sign it then adjusts to the speed limit +2. If the speed limit changes, the car does not change speed unless I tap on the speed limit sign again. The only time the car changes the set speed is for things like going around curves in cloverleafs or off-ramps.

Maybe if you have EAP or FSD, TACC behaves differently?

If so, that could partially explain why some kinds of phantom braking are being experienced more by some people than others. Perhaps some of the problems (like driving under an overpass and having the speed briefly switch to the speed limit of the road above) are only a problem for people with EAP/FSD?
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
10,010
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
If so, that could partially explain why some kinds of phantom braking are being experienced more by some people than others. Perhaps some of the problems (like driving under an overpass and having the speed briefly switch to the speed limit of the road above) are only a problem for people with EAP/FSD?
some have been talking about phantom braking while others dont have issues since before they re-arranged EAP to AP, so dont think it's that.
 

SimonMatthews

Well-known member
Joined
Apr 20, 2018
Messages
255
Location
Fremont, CA
Tesla Owner
Model 3
Country
Country
The last few days, I have been experiencing an unexplained slowdown in the same place -- i880N in Milpitas. Today, my car was down to 20mph with nothing in front, the display showing the speed limit as 65mph, no bridges or under/overpasses. It appears to do this quite reliably.
 

Klaus-rf

Well-known member
Joined
Mar 6, 2019
Messages
293
Location
SoCal
Tesla Owner
Model 3
Country
Country
Summary:
Had an interesting braking event today on fwy using NoAP. The braking was expected for AP (I personally would not have slowed down at all) while TACC was soooo slow resuming speed that I had a semi less than a foot off my rear bumper. AP really needs to learn about rear traffic.

Details:
4-lane fwy and I was at Speed Limit +5 ( aka 70 MPH) in lane 3. A vehicle in front of me in lane 2 swithed on its right blinker and made a slow, smooth move across two lanes passing in front of me about 80 feet ahead, moving steadily to lane 4. TACC slowed down - not severely, more like normal regen braking, then stopped slowing, maintaining speed. Traffic (semi truck) came up behind me FAST! Then TACC/AP very slooowly began to resume previous speed. The slow acceleration is a serious problem, imho.

As soon as I saw the semi trying to collect its first Tesla bumper ornament, I added power to get out of its way.

TACC/AP needs to learn about rear coming traffic. Very dangerous how it works now.
 

garsh

Dis Member
Moderator
TOO Supporting Member
Joined
Apr 4, 2016
Messages
11,789
Location
Pittsburgh PA
Tesla Owner
Model 3
Country
Country
I think on a long trip on major highways we might put the offset back to 0.
I simply leave mine at -20 mph.
All it really means is that I need to manually accelerate up to my desired speed. I find that to be an acceptable tradeoff to having the car accelerate by itself when I'm not expecting it and don't desire it.
 

mswlogo

Top-Contributor
Joined
Oct 8, 2018
Messages
719
Location
MA
Tesla Owner
Model 3
Country
Country
Hmm...this thread is making me think: is it possible that some forms of phantom braking are more of a problem for people with EAP or FSD than AP?



That's not what happens for me--and I have just AP, with the offset set at +2. When I engage TACC, AP just sets the speed to whatever speed I was going. If I tap on the speed limit sign it then adjusts to the speed limit +2. If the speed limit changes, the car does not change speed unless I tap on the speed limit sign again. The only time the car changes the set speed is for things like going around curves in cloverleafs or off-ramps.

Maybe if you have EAP or FSD, TACC behaves differently?

If so, that could partially explain why some kinds of phantom braking are being experienced more by some people than others. Perhaps some of the problems (like driving under an overpass and having the speed briefly switch to the speed limit of the road above) are only a problem for people with EAP/FSD?
If you are below PSL ( Posted Speed Limit) TACC will bring you up to that speed when engaged.

If you are above PSL it will just match your speed.

The “Offset” adjusts what TACC uses for PSL.

The problem has nothing to do with Auto Steer (AP or EAP or NoA).
 

Technical48

Active member
Joined
Apr 29, 2018
Messages
111
Location
Oviedo, FL
Tesla Owner
Model 3
Country
Country
(IOW, I have my foot over the accelerator ready to keep it at the cruising speed).
This right here is a major reason why I'm glad I didn't buy the EAP option. If I'm operating on cruise control I keep my right foot poised for the BRAKE pedal. Ridiculous that EAP forces you to be ready for quick accelerator applications just to avoid getting rear-ended or to avoid a road rage incident because somebody thinks you're brake-checking. I just don't see how EAP is relaxing for anybody unless you're driving on a completely empty road in the middle of nowhere. During the trials that was the only situation where I liked using EAP.
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
10,010
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
This right here is a major reason why I'm glad I didn't buy the EAP option. If I'm operating on cruise control I keep my right foot poised for the BRAKE pedal. Ridiculous that EAP forces you to be ready for quick accelerator applications just to avoid getting rear-ended or to avoid a road rage incident because somebody thinks you're brake-checking. I just don't see how EAP is relaxing for anybody unless you're driving on a completely empty road in the middle of nowhere. During the trials that was the only situation where I liked using EAP.
unless you have driven with EAP, you don't get the benefits vs the inconveniences. I don't keep my foot over the accelerator because I think otherwise Id be rear ended - but because Ive learned under specific traffic conditions, the car will slow at specific points. It is no more slowing than any other car driven by a person may do, and no where in the post you quoted from me did I say it slowed to a degree that I worried about being rear ended.
 

DocScott

Well-known member
TOO Supporting Member
Joined
Mar 6, 2019
Messages
341
Location
Westchester, NY
Tesla Owner
Model 3
Country
Country
Summary:
Had an interesting braking event today on fwy using NoAP. The braking was expected for AP (I personally would not have slowed down at all) while TACC was soooo slow resuming speed that I had a semi less than a foot off my rear bumper. AP really needs to learn about rear traffic.

Details:
4-lane fwy and I was at Speed Limit +5 ( aka 70 MPH) in lane 3. A vehicle in front of me in lane 2 swithed on its right blinker and made a slow, smooth move across two lanes passing in front of me about 80 feet ahead, moving steadily to lane 4. TACC slowed down - not severely, more like normal regen braking, then stopped slowing, maintaining speed. Traffic (semi truck) came up behind me FAST! Then TACC/AP very slooowly began to resume previous speed. The slow acceleration is a serious problem, imho.

As soon as I saw the semi trying to collect its first Tesla bumper ornament, I added power to get out of its way.

TACC/AP needs to learn about rear coming traffic. Very dangerous how it works now.
That just sounds like an obnoxious semi to me. I've had plenty of experiences like what you describe long before I owned a Tesla. Does that make me a dangerous driver?

I think part of what we'll start encountering as AP gets better is that different people drive very differently, and there's a wide range of behaviors which are consistent with safe and effective driving. "AP doesn't do what I would have done" will always be the case for the vast majority of people, because if you put any other human driver in your car it's very unlikely they'll consistently do what you would have done. But you notice it more when you're the one monitoring it, sitting in the driver's seat and holding the steering wheel.
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
10,010
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
I think part of what we'll start encountering as AP gets better is that different people drive very differently, and there's a wide range of behaviors which are consistent with safe and effective driving. "AP doesn't do what I would have done" will always be the case for the vast majority of people, because if you put any other human driver in your car it's very unlikely they'll consistently do what you would have done. But you notice it more when you're the one monitoring it, sitting in the driver's seat and holding the steering wheel.
I think THIS is why some owners have different gripes about (E)AP for the last couple years. Some see it being cautious in a situation as a bug that needs to be fixed. Some see it being confident in some situations as it being a bug that needs to be fixed.
Overall, I drive near the speed limit (when not forced by traffic to be barely moving), I let merging traffic merge, I expect adjacent cars will do something stupid and am waiting to intervene when they do, etc....
rarely have I had (E)AP act in a way that I thought was wrong. I think that has more to do with my driving personality being in line with how (E)AP is programed than my car or route giving different results than someone that is always having 'bugs' with theirs.
 

Klaus-rf

Well-known member
Joined
Mar 6, 2019
Messages
293
Location
SoCal
Tesla Owner
Model 3
Country
Country
That just sounds like an obnoxious semi to me.
May be. But NoAP (TACC / AP) didn't even now it was there. If it brakes for something minor in front, shouldn't it then accelerate or move out of the way for something serious behind? Don't we teach human drivers to check all mirrors periodically and adjust [lane / speed / etc.] accordingly??

IMHO the design needs a rear-facing RADAR. It currently has no idea about rear facing traffic. THAT IS DANGEROUS.

Reminds me of an airplane autopilot system that could easily do automated take-offs but couldn't land. BTW - AP landing capabilities have been in commercial airplanes since at least 1977. ( Might not have been FAA Approved then, but the planes were fully capable of landing using AP alone including putting the gear down. )
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
10,010
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
shouldn't it then accelerate or move out of the way for something serious behind? Don't we teach human drivers to check all mirrors periodically and adjust [lane / speed / etc.] accordingly??
at least here, no. drivers ed and defensive driving doesnt tell people they should speed up because someone behind them is speeding up. get out of the way, if you are blocking faster traffic, yes. but to speed up, no.
 

DocScott

Well-known member
TOO Supporting Member
Joined
Mar 6, 2019
Messages
341
Location
Westchester, NY
Tesla Owner
Model 3
Country
Country
Hmm...this thread is making me think: is it possible that some forms of phantom braking are more of a problem for people with EAP or FSD than AP?



That's not what happens for me--and I have just AP, with the offset set at +2. When I engage TACC, AP just sets the speed to whatever speed I was going. If I tap on the speed limit sign it then adjusts to the speed limit +2. If the speed limit changes, the car does not change speed unless I tap on the speed limit sign again. The only time the car changes the set speed is for things like going around curves in cloverleafs or off-ramps.

Maybe if you have EAP or FSD, TACC behaves differently?

If so, that could partially explain why some kinds of phantom braking are being experienced more by some people than others. Perhaps some of the problems (like driving under an overpass and having the speed briefly switch to the speed limit of the road above) are only a problem for people with EAP/FSD?
I stand corrected.

I got the perfect chance to test this out today, because I brought by Model 3 with AP in for service and then got a Model S with EAP as a loaner. So I drove it across the same section of road...and they behaved pretty much identically with respect to TACC speed.

First off, I was wrong: on today's trips, TACC usually set an initial speed based on the speed limit if I'm going slower than the limit. But for some reason, not always. And if I was going faster than the speed limit-based speed when I engaged TACC, it engaged at the faster speed.

But for both cars, when the speed limit increased on the road I was on the speed limit sign on the display registered the increase, but TACC did not increase the set speed to match. It would probably do if NOA were on, but not for just TACC. If the speed limit on the road decreased, it would sometimes decrease the set speed to what it thought was safe (e.g. speed limit +5), but again it wouldn't be decreasing it to speed limit plus offset; with my offset at +2, it was generally faster than that.

tl;dr: TACC set speeds behave the same whether the car has AP or EAP. When on TACC (but not NOA), TACC does not adjust the set speed when the speed limit on the road changes, unless the speed limit dropped and the car would then be travelling at an excessive speed.
 

Mr. Spacely

Well-known member
TOO Supporting Member
Joined
Feb 28, 2019
Messages
367
Location
St. Petersburg, FL
Tesla Owner
Model 3
Country
Country
Klaus-RF said: "Reminds me of an airplane autopilot system that could easily do automated take-offs but couldn't land. BTW - AP landing capabilities have been in commercial airplanes since at least 1977. ( Might not have been FAA Approved then, but the planes were fully capable of landing using AP alone including putting the gear down. )

Not exactly. 99% of all landings and 100% of takeoffs are still done by pilots. And it was only in the last 7-8 years that planes could even attempt to self land. Basically autopilot will get you lined up and very close to the ground, but the pilot has to have a visual of the runway or he/she will abort the landing...
 

Klaus-rf

Well-known member
Joined
Mar 6, 2019
Messages
293
Location
SoCal
Tesla Owner
Model 3
Country
Country
Klaus-RF said: "Reminds me of an airplane autopilot system that could easily do automated take-offs but couldn't land. BTW - AP landing capabilities have been in commercial airplanes since at least 1977. ( Might not have been FAA Approved then, but the planes were fully capable of landing using AP alone including putting the gear down. )

Not exactly. 99% of all landings and 100% of takeoffs are still done by pilots. And it was only in the last 7-8 years that planes could even attempt to self land. Basically autopilot will get you lined up and very close to the ground, but the pilot has to have a visual of the runway or he/she will abort the landing...
I agree that those are the FAA's rules. I'm saying that the AP in the planes has been fully capable of doing AP-only landings for decades. Perhaps we could call it "Beta"?

I used to work (on the technical side) at a flight training facility at LAX in the late 70's (owned by Flying Tigers). We had an old DC-8 sim and a newer Lynx 747 simulator unit. Both system were fully capable of landing the planes using AP. We used to test them in the Hong Kong airport with the mountain profiles programmed in. Fun stuff.
 

SimonMatthews

Well-known member
Joined
Apr 20, 2018
Messages
255
Location
Fremont, CA
Tesla Owner
Model 3
Country
Country
The last few days, I have been experiencing an unexplained slowdown in the same place -- i880N in Milpitas. Today, my car was down to 20mph with nothing in front, the display showing the speed limit as 65mph, no bridges or under/overpasses. It appears to do this quite reliably.
Didn't happen today, somewhat earlier in the day. Perhaps it is shadows of the dividers, signposts or lights on the road that is causing it. There is nothing on the screen to indicate anything that needed to be avoided.
 

SimonMatthews

Well-known member
Joined
Apr 20, 2018
Messages
255
Location
Fremont, CA
Tesla Owner
Model 3
Country
Country
Klaus-RF said: "Reminds me of an airplane autopilot system that could easily do automated take-offs but couldn't land. BTW - AP landing capabilities have been in commercial airplanes since at least 1977. ( Might not have been FAA Approved then, but the planes were fully capable of landing using AP alone including putting the gear down. )

And it was only in the last 7-8 years that planes could even attempt to self land.
Go look at the history of Autoland .... it dates back to the '60s.
 

Klaus-rf

Well-known member
Joined
Mar 6, 2019
Messages
293
Location
SoCal
Tesla Owner
Model 3
Country
Country
at least here, no. drivers ed and defensive driving doesnt tell people they should speed up because someone behind them is speeding up. get out of the way, if you are blocking faster traffic, yes. but to speed up, no.
I beg to differ. Drives that are going too slow get cited for it - because it's dangerous.