[vegardx]

I don't think Tesla reads signs at all. As far as I understand they're using map data, which is often out of date. It's one of those features that is so bad that they really should give you an option to just disable it. But I guess that would be an admission of poor implementation.

It's one of those things that the entire industry seems to have solved 10-15 years ago that Tesla just can't get right. That and automatic or even functioning windscreen wipers.

[CorrectHorseBat]

I'm 99% sure it doesn't use map data (or they bought horrible data in Belgium), but I'm not sure it uses real time detecting software. Maybe it crowd sources data from other Teslas?

I'm sure because it makes mistakes only sign detection software would make. It doesn't know speed limits end at an intersection and makes this mistake all the time. Also sometimes it detects max 10 ton as max 10kmph. I don't think it's real time because it doesn't detect road works speed limits reliably. (But I think there was an update recently saying it's real time now, so maybe it changed)

[AYBABTME]

Afaict in the US it uses camera to read posted signs, and it doesn't understand it so well. Again and again I had my car interpret a speed sign wrongly and change it's behaviour in consequence.

Whereas my Ioniq 5 in Korea has perfect knowledge of the speed limits, all speed camera locations, all exceptions, etc, and presents it in the windshield under the wheels of the car in front of me. Night and day.

In general Tesla relies too much on AI and not enough on boring factual/external data sources/information.

[mgoetzke]

It definitely reads the signs. That has been proven many times over (with temporary signs etc, or handheld signs) visualized correctly in the 3d view, but it decides to ignore them often. The assumption is an override from the Maps, but that alone does not explain everything.

[vegardx]

I might be wrong, but I think this is where a lot of the misconception stems from. In Norway it also shows the (usually) correct visualization, but it never use it. People have done a lot of testing and it seemingly always use map data. But this might be different in different regions. From my understanding this is where a lot of the "phantom breaking" on highways comes from. The map data shows a temporary slower speed sign due to previous construction.

[averageRoyalty]

In Australia, a lot of buses have a 40kmph sign on the back to show you should pass the bus at 40 when stopped - but it's laid out and coloured the same as road signs.

Every time I'm behind a bus in my Tesla, it reads the sign on the bus, displays it on the scren as the current limit, and sometimes (arbitrarily it seems) if I have autopilot on it reduces the maximum allowed speed to 40.

I can't speak for the logic run elsewhere, but AU Teslas for sure use it.

[ngcc_hk]

At least Google map and in uk is not outdated. Seems most if not all the time ok on speed time. I was surprise by it.

(Not sure about major road repair but that is understandable.)