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Speed signs not detected by Teslas?

GeorgeSymonds

Active Member
Moderator
Mar 16, 2018
2,518
2,787
UK
I don’t think speed limits has anything to do with FSD.

For me:

Two way roads sometimes seem to work, both see and adjust your speed
Dual carriageway it might see but rarely, if ever adjust
Motorways it doesn’t even see them

It’s also not the amount of speed, ie only works at 40 or below, because it works in national speed limits 2 way roads.

This is almost completely the opposite way to what I want as I’m most likely to use it in motorways, and least likely on 2 way roads.
 

Adopado

Well-Known Member
Aug 19, 2019
6,506
5,016
Scotland
It has the worst speed limit sign recognition of any car I’ve had. There are long term roadworks near me and the car doesn’t see a single one of the 15+ 50mph signs. But a few miles away, similar roadworks, same class of road, it sees them all.
Do you mean on a motorway? My Model 3 is pretty reliable at reading speed signs but this feature is not enabled for motorways.
 

Adopado

Well-Known Member
Aug 19, 2019
6,506
5,016
Scotland
I've only had my Model Y a couple of days, but today I got to drive extensively on a range of different roads. The biggest surprise to me is that Tesla's (or mine anyway) do not detect speed signs. My last couple of cars have both had this ability, so it surprised me that Tesla's seem to use map data only, which is quite unreliable. Do I have a fault?
Should detect speed signs other than on motorways.
 
I don’t think speed limits has anything to do with FSD.

For me:

Two way roads sometimes seem to work, both see and adjust your speed
Dual carriageway it might see but rarely, if ever adjust
Motorways it doesn’t even see them

It’s also not the amount of speed, ie only works at 40 or below, because it works in national speed limits 2 way roads.

This is almost completely the opposite way to what I want as I’m most likely to use it in motorways, and least likely on 2 way roads.
Adjusting speed I am not expecting. Just plain detecting them seems to me to be based on GPS data. Yesterday on a variable speed limit section of motorway and through roadworks that were clearly signed it detected nothing. Both were faster roads though, so maybe as you say, Teslas can't cope with faster speeds.
 
Adjusting speed I am not expecting. Just plain detecting them seems to me to be based on GPS data. Yesterday on a variable speed limit section of motorway and through roadworks that were clearly signed it detected nothing. Both were faster roads though, so maybe as you say, Teslas can't cope with faster speeds.
Ah, I just found in the manual that they can read signs but only if they conform to standard designs. I suspect that may explain the variable speed limits not working
 

GeorgeSymonds

Active Member
Moderator
Mar 16, 2018
2,518
2,787
UK
Adjusting speed I am not expecting. Just plain detecting them seems to me to be based on GPS data. Yesterday on a variable speed limit section of motorway and through roadworks that were clearly signed it detected nothing. Both were faster roads though, so maybe as you say, Teslas can't cope with faster speeds.
I’m saying the opposite, speed limits work fine in a 60 mph area, but do 50 on a motorway in a variable speed zone and it refuses to see them. It seems it’s the type of road where it doesn’t work. Some blame Mobileye who have the patent, and cars with AP1 (which is Mobileye) work more or less fine, and that tech is getting old, so I doubt it’s speed as such. Some say they’re just avoiding paying a license fee or breaching patent laws by doing it some convoluted way.

On TACC/cruise, you’d expect it to adjust the speed. There’s a video showing it working on different road types

 

Undecided_2

Member
Supporting Member
Jan 21, 2022
601
433
Helensburgh
Liking the smooth power delivery.
My wife thought she’d be able to cope with the harshness of the ride, but it’s proving a deal breaker. We’re having a long run out today, so we’ll see.
Liking the fancy iPad screen
Liking the remote connectivity
Finding the driving technology underwhelming. This has been the biggest surprise.
Overall, its Ok. Pleased to be in an EV, but ride might break the deal and my wife’s back.
I just checked the tire pressures on my MY. They were 50psi. I dropped them to 42psi as per the sticker on the door.

Huge difference. Way less crash. My wife noticed the difference.
 
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GRiLLA

Active Member
Jul 5, 2020
2,089
2,277
UK
Some jumbled information in this thread, it's really best to refer to the manual that does describe all the driving features.

1. FSD is not required to read road signs, it's included in all cars.
2. Tesla does not read speed signs on Motorways, it uses GPS data. It's simply not currently an included feature yet, maybe in the future. Scroll the right thumbwheel to set the limit manually to speed reductions. The current software will never recognise that 50mph roadworks section on your local motorway.
3. On other roads it will use map data first, but then override that with actual seen signs.
4. If TACC is set to engage at the speed limit it will continue to follow the detected limit, but if it's set to engage at current speed it will not.

For a long time it was assumed that Tesla couldn't implement speed sign reading at all due to the patent held by Mobileye, but they launched it in 2020 in it's current form and were not challenged. Map data takes maybe a year to be updated if a speed limit is changed.
 

WannabeOwner

Well-Known Member
Nov 2, 2015
6,969
3,736
Suffolk, UK
If it works really well then most of the time it would recognize speed signs but other times would not.

When I had the first MS (MobileEye AP) it recognised speed signs ... including the one on A1 just North of Peterborough which has a (50) Roundel with "In 1/2 mile" under it ... slammed on the brakes and caused heart attack for anyone behind me ...

Seems to not read speed limit signs on A roads and motorways

Not sure about A-Roads - dual carriageway maybe? On the A road near me it slows down for 40, then 30, then speeds up from 20 to 40, and once out of the limit then 40 to 60.

On motorways (and my guess would be "all 70MPH Dual Carriageway roads") then, yes, Nada.

EAP is pretty much pointless, right now, for me. It doesn’t make driving less stressful/easy as it doesn’t slow for changes in speed limits/temp road signs.

EAP definitely slows for fixed speed limits for me

phantom braking is when your cruising along and it brakes with no warnings and for no apparent reason. That happens to me now and then, typically when passing a lorry

Not done any testing myself, as yet, so just passing this on. Someone told me that braking whilst passing a lorry is not "phantom braking" and that if I record on the dashcam, and review it, I will see that the lorry moved towards me.

For me, that's the only "sudden brake" that I get. I don't get any for gantries / bridges etc which I read other people experiencing. No idea why that would be (and, for me, has been the same with MS, M3 and MY that I have owned). Dunno if sensor-adjustment could therefore be responsible on cars that have that often.

braking wouldn’t prevent a collision if that was the case. Most of the time it could have swerved to the right

Exactly. I've seen plenty of YouTube videos where the car physically moved in lane when someone in adjacent lane started intruding ... so sudden-brake, rather than "move over", when overtaking and vehicle in inside lane "moves slightly" seems improbable (thus seems more likely, to me, to be "software not yet solved that one")

the fact it doesn’t read the new speed and give you an option to quickly change it is the real issue

IF the dashboard is showing the correct speed "roundel" you can touch that to set it as your max cruise speed (I expect you know that, and that what you are saying is that the "roundel" does not change, because either speed sign was not recognised, or GPS database is wrong ... so only mentioning in case you were not aware)
 

WannabeOwner

Well-Known Member
Nov 2, 2015
6,969
3,736
Suffolk, UK
Ah, I just found in the manual that they can read signs but only if they conform to standard designs. I suspect that may explain the variable speed limits not working

Its not just that. Overhead gantry (light array signs) don't look like roundels and, yes, not recognised. But pucker roundel signs aren't recognised on motorways either.

If TACC is set to engage at the speed limit it will continue to follow the detected limit, but if it's set to engage at current speed it will not.

I have TACC set to engage-at-current-speed and it slows for speed limits.

My experience is:

On A-Road set TACC to 60 MPH.

Enter a 40 or 30 - the car slows. (including if limit then changes from 40 to 30)
Come out of the speed limit and car speeds back up. (including from 30 to 40, or an end-of-limit sign)

START the journey in a 30 or 40 - set TACC to limit. Car will NOT speed up on exiting limit.

START in a 40, and then enter a 30, car will slow (and speed back up 30-to-40 ... but not sure I have anywhere I can try that to see what, then, happens when you eventually come out of the original 40 area. I suspect it won't speed up above 40 until it has, at some point, been manually adjusted on a road that has a higher limit.
 

GRiLLA

Active Member
Jul 5, 2020
2,089
2,277
UK
Its not just that. Overhead gantry (light array signs) don't look like roundels and, yes, not recognised. But pucker roundel signs aren't recognised on motorways either.



I have TACC set to engage-at-current-speed and it slows for speed limits.

My experience is:

On A-Road set TACC to 60 MPH.

Enter a 40 or 30 - the car slows. (including if limit then changes from 40 to 30)
Come out of the speed limit and car speeds back up. (including from 30 to 40, or an end-of-limit sign)

START the journey in a 30 or 40 - set TACC to limit. Car will NOT speed up on exiting limit.

START in a 40, and then enter a 30, car will slow (and speed back up 30-to-40 ... but not sure I have anywhere I can try that to see what, then, happens when you eventually come out of the original 40 area. I suspect it won't speed up above 40 until it has, at some point, been manually adjusted on a road that has a higher limit.
Agreed, it will not exceed the speed at which is was set on TACC, but I think that's a different behaviour on AP. Not documented.

I'm very happy for folks to complain that it's rubbish that Tesla don't try to detect speeds on motorways, but so many seems to think it's just not spotting things. The software is working as intended. There are many more ways in which speeds are expressed on Motorways, on other roads there is a common pattern of number within red circle with white background. On a motorway there are boards, gantries of multiple configurations, limits that apply to specific lanes, central reservation screens, advisory limits etc. My MobileEye equipped Leaf is only right about 50% of the time.
 
I have TACC set to engage-at-current-speed and it slows for speed limits.

My experience is:

On A-Road set TACC to 60 MPH.

Enter a 40 or 30 - the car slows. (including if limit then changes from 40 to 30)
Come out of the speed limit and car speeds back up. (including from 30 to 40, or an end-of-limit sign)

START the journey in a 30 or 40 - set TACC to limit. Car will NOT speed up on exiting limit.

START in a 40, and then enter a 30, car will slow (and speed back up 30-to-40 ... but not sure I have anywhere I can try that to see what, then, happens when you eventually come out of the original 40 area. I suspect it won't speed up above 40 until it has, at some point, been manually adjusted on a road that has a higher limit.
This is really interesting because I have set at current speed and it ignores speed limits (which is often what i want) but it does mess around with the "fleet speed" thing, which is one of the worst ideas I have ever heard.
 
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Casss

Member
Aug 6, 2021
596
579
UK
If FSD could identify smart gantries, that'd be great.

If FSD could identify smart gantries and deploy a laser that cut them off at the base at an appropriate angle so that they fall away from the motorway destroyed, leaving room for a hard shoulder that'd be even better. Bring back dumb motorways. Thanks for coming to my TED talk.
 

Undecided_2

Member
Supporting Member
Jan 21, 2022
601
433
Helensburgh
Please could someone confirm the speed sign limits and changing speed. My experience is that it appears the GPS decides a speed limit. If I pass through temporary speed signs the EAP doesn’t change the speed. If it does detect a speed sign I have to tap the screen to get the car to slow, it’s not automatic.

Am I using it incorrectly? What type of roads is it designed to work on?
 

GRiLLA

Active Member
Jul 5, 2020
2,089
2,277
UK
Please could someone confirm the speed sign limits and changing speed. My experience is that it appears the GPS decides a speed limit. If I pass through temporary speed signs the EAP doesn’t change the speed. If it does detect a speed sign I have to tap the screen to get the car to slow, it’s not automatic.

Am I using it incorrectly? What type of roads is it designed to work on?
If you are on a motorway then it will only use the map data, won't see road signs. If you are not on a motorway it will see road signs.

TACC will react to road signs if it is set to engage at the current speed limit, not if at current speed.
 
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It's one of those wierd Tesla things that the speed limits are completely random and confusing. I've *never* had my car adjust for speed limits - always have to do it myself - on both TACC and AP, with or without FSD. But for some people it works.. almost like they have different software somehow, which wouldn't make sense (A/B testing is a thing but not for 3 years...).
 
Saw an amusing one today. Car wash on my drive home have put up an advertising stand for new promotion, and it includes a 25% discount. It's not anything like a speed limit sign other than it has a circular background on the 25% The car picked it up both as a new speed limit and showed it as a speed lollipop on the visualisation.

I've had the car recognise my house number as a speed limit before.. my house number looks absolutely nothing like a speed limit.

And yet the clearly defined and obvious speed limit signs on the local A road it can't see...
 

Undecided_2

Member
Supporting Member
Jan 21, 2022
601
433
Helensburgh
If you are on a motorway then it will only use the map data, won't see road signs. If you are not on a motorway it will see road signs.

TACC will react to road signs if it is set to engage at the current speed limit, not if at current speed.
I would have thought motorways would have been easier for them to program. Local roads near me are littered with road signs. It’s on long journeys that I want to have an easier drive, not local roads.
 

GRiLLA

Active Member
Jul 5, 2020
2,089
2,277
UK
I would have thought motorways would have been easier for them to program. Local roads near me are littered with road signs. It’s on long journeys that I want to have an easier drive, not local roads.
Local roads follow a neat pattern that i straight forward to train, a red circle with either 20, 30, 40 or 50 or national speed limit. Motorways have gantries with many different types of digital signs, roadworks signs, central reservations boards, sometimes different speeds for lanes, advisory limits etc. Tesla simply hasn't trained the cars AI to attenpt to recognise UK speed limits on motorways yet.
 

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