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Discussion Starter · #1 ·
For a moment last night, I got excited, when I saw my M3 start to download the EU 2021 map to replace the already out of date 2019 navigation which came with the car when I took delivery in October 2020.

I was hoping, in particular, that the incorrect speed limits would have been fixed.

But no. On my test drive today, it thought that the limit was 30mph on a 60mph road, and then, worse still, 40mph in a 30mph, which could have been dangerous.

Even when it did detect a speed limit change from 40mph to 30mph, it made no attempt to reduce the speed on Autopilot (I have EAP), but just continued on at the previous 40mph.

What a shame.

I didn't get the chance to test this today, but I wonder if they have fixed the incorrect roundabout exit announcements when, for example, the car says take the second exit but it's the third exit on the screen.

Why not just use Google maps or allow the driver to use Google maps or Waze via Android Auto or Apple Car Play, if they can't get their own navigation system working properly?
 

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AP only responds to speed limit changes on a few roads. Almost none around here, but others have found it does on their local roads.. it's seemingly random.

I'm glad that's still broken though as otherwise when it got the speed limit wrong it could force you to slow to dangerously slow speeds.
 

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I have an ordinary main road 30mph that shows up as 20mph, one that shows up as 40mph, and if I drive across the roundabout over the motorway near work, it shows 70 on the 40!!
 

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Discussion Starter · #8 ·
With regards to speed limits, isn't the car supposed to recognise speed signs? Mine doesn't seem to do that. Is there a setting that I need to adjust or something? Or is this only available with the FSD package?
I'm pretty sure that it does not "see" speed limit signs but relies on GPS data.

My old Leaf used to see signs and even motorway temporary limit signs on the gantry which was more accurate.
 

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I'm pretty sure that it does not "see" speed limit signs but relies on GPS data.

My old Leaf used to see signs and even motorway temporary limit signs on the gantry which was more accurate.
Did a quick Google search and it does recognise speed signs and adjusts the speed accordingly. Apparently there is a setting that you have to adjust as outlined in the below article.


“In addition to local roads, Speed Assist now leverages your car’s cameras to detect speed limit signs to improve the accuracy of speed limit data for highways. As usual, to adjust Speed Assist settings, tap Controls > Autopilot > Speed Limit.”

I've basically just answered my own question haha :D
 

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The car indeed reads and understands speed limit signs, even temporary ones, and it renders on the screen.

On UK motorways, dual carriageways, etc., the car doesn't seems act on speed limit changes that contradict its map database, probably to avoid picking up signs meant for slip roads and reduce your speed from 70 to 30 mistakenly.

On local roads on autopilot the car should slow down if there's a speed limit sign changing the speed say from 60 to 40, and if you manage not to disengage Autopilot, it will speed you up back to 60 when there's a 60 or NSL sign again. Although people have mixed results with this.
 

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Discussion Starter · #11 ·
Did a quick Google search and it does recognise speed signs and adjusts the speed accordingly. Apparently there is a setting that you have to adjust as outlined in the below article.


“In addition to local roads, Speed Assist now leverages your car’s cameras to detect speed limit signs to improve the accuracy of speed limit data for highways. As usual, to adjust Speed Assist settings, tap Controls > Autopilot > Speed Limit.”

I've basically just answered my own question haha :D
That section of the settings does not active a camera to read speed limits. On my car it sets the cruise control to be at the speed limit or the current speed.
 

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The speed limit sign reading isn't great though. For example, there's a 50 limit road near me that as you approach a village has two "countdown" signs showing that the limit changes in 300 yards and again at 100yds.

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The Tesla reads the first sign as a speed limit and ignores the 300 yard part. The displayed speed limit on screen changes to 30 (it didn't used to when it relied only on GPS data).

However, at 200 yards before the 30 limit there's a 50 limit repeater sign, so the displayed limit on screen goes back to 50. Then at 100 yards there's another 30 limit warning board, and it flips back to 30 again.


Another thing it mishandles is school zones:

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It displays 20mph on screen at all times of day (again, it did not do this prior to the update that introduced reading speed limit signs). This is something that you'd think that Tesla would have got right because school zone speed limits (when lights flashing) are WAY more commonplace in the USA than they are in the UK.

The Leaf uses Mobileye and there's some patent that mobileye have that prevents tesla from doing certain things with speed limit recognition that particularly affects overhead signs, thus the tesla system makes no attempt to read signs on overhead gantries.
 

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Hmmm sounds like the speed sign recognition is more hassle than it's worth. I'll have a dig around in the settings and activate it to test it out. If it's rubbish, I'll probably just keep it off.
That's the issue, I don't think speed limit sign recognition is something you can deactivate, it is always on.

What you can change is how TACC and Autopilot behaves when activating: current speed or speed limit (whatever the car thinks it's the speed limit).

On local roads, if the car thinks the speed limit is lower than the correct one, you're stuck with the lower limit for Autopilot (plus any offset you set?), but a workaround is using TACC only which allows any set speed and steer the car yourself. On dual carriageways I'm usually able to set a faster speed than what the car reads for Autopilot.
 

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The small estate that I live on (been up for 30+ years and one road in and out) has no speed limit sign at the road end as it is coming off a 30MPH road anyway but the car insists it is in a 60. Another road not that far away has the NSL signs at the end of each of the villages at either end of it, one is a 30 and the other is a 40, but the car displays 40 for the stretch of road between, irrespective of which direction you are travelling
 

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I sort of convinced myself the car could only recognise the lollipop signs in the UK but nothing else. I passed a 10mph on a couple of private roads and it seemed to work so there wouldn't be a GPS for those, unamusingly it actually got stuck on one and it was chiming at me for what seemed like miles afterwards on a single track road. The other reason I thought it was the case was it was stuck at 70mph through the M27 "smart" motorway workings rather than showing the 50mph average speed limit which is everywhere. I think the Tesla is actually better than the Polestar which spent a lot of time flip flopping around 50,60 and 30,40 for what appeared to be no good reason. No signs or close by other roads which might have confused. Not that is much of a consolation if you are trying to avoid an unnecessary ticket.
 

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The car often seems to pick speed limits at random based on things it sees even when it isn't the correct location for that limit and clearly refers to a side road.

I even had it picking up a hand made 20mph sign someone had nailed to a tree by their driveway.

Other times - like the huge speed limit signs on the A556 - it completely misses them...

Totally unreliable.
 

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Having driven around in a Corsa with and without a Satnav but with the speed limit sign recognition you can tell just how crap the visual system is. Without maps to back it up the non satnav corsa was showing --- much of the time and the wrong speed limit a lot of the rest of the time unless you happened to be on a dual carriageway or somewhere else where there were two signs for it to catch. Both also tended to pick up the 5 mph limits at a local sorting office. The satnav backed car was generally rarely showing --- and apart from when switching between nsl and a specific limit was generally ok. That was probably right 80% of the time over all. Which still isn't good enough for any automatic speed limiting system.

Without a legal requirement for repeaters in all limits, including 30s, on both sides of the road then I can't see them ever being reliable.
 
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