My understanding is that the stop sign recognition system works from known stop sign locations from the Nav software and also from the front radar recognizing what a sign looks like. Since the only red, octoganal street signs are stop signs I would think the language doesn't matter. But maybe the letters are part of the recognition programming too.
If we have any members from Mexico it would be interesting to see how the system works there.
I was told by my sales guy (yeh, I know) that the NAV system provides speed limits even when there are no posted signs. He also told me that on his way to pick me up, the HUD displayed a Speed Limit that conflicted with what was posted, but I believe he was in an unfamiliar part of the interstate where the speed limit steps down as it goes into congested areas.
So I don't know if the sign "recognition" is a combination of Seen-by-Camera + NAV Database, or if it is just NAV Database alone. I do know that the Speed Limit signs that display on the HUD are from a collection of icons stored on the NAV card...they are not renditions of what the camera sees. There are separate database icons for Speed Limit 35, Speed Limit 55, etc. This is one reason why the NAV Card must be inserted in order for the system to work.
I live in a rural area where you can go quite a while without seeing the speed limit posted again for miles. I've driven down such roads where at some point the Speed Limit icon on the HUD just goes away. We have "Speed Limit Ends" roads, but those are posted as such. In some instances, the icon just disappears when the system goes for a while without seeing a sign. Perhaps there's a blot in the database for some of these rural areas. But you would think that the last seen sign would be retained until replacement data says otherwise. Or maybe these are "Speed Limit Ends" areas that are missing their signage (so the database governs and I don't know that the speed limit ended).
One of these days I would like to test some of this. I would like to cover up a Stop sign or Speed Limit sign and see if the system still displays the icon just because the NAV system says one should be at those coordinates. I'd like to erect a sign at some random spot to see if the system sees it and responds accordingly even though the NAV database does not contain one at those coordinates. I'd like to run a Stop sign and see if the system screams BRAKE!!!
Regarding the Stop sign issue folks have posted, I agree that the shape is what's recognized and not the wording. But if you are correct about the NAV database knowing where Stop signs are, then recognition should be irrelevant.
Regarding school Speed Limit signs...my system has never recognized one of those (either by camera or by NAV database), but the ones here have 2 flashing yellow lights mounted in the signs, which might prevent recognition. Besides, how would the system know whether or not school is in session (time of day/day of week/time of the year/holidays)?
