Wait wait what? The traffic signs in the US are not pictograms but... Plain text????
Wh.. what???
Wha? Signs in the US are often pictograms. That's just an uncommon sign.
According to that Wikipedia link, there is no other sign for "do not pass" that is not black text on a while background. Is "do not pass" an uncommon sign? Because over here may be one of the most common ones.
About half the regulatory signs in that link are just black (English) text on a rectangular white sign .
There is also this sign, which is used more commonly than the white rectangle variant.
I recognize that this is also text on a background (yellow) but this sign is also basically the only one that shape ever. (Not as good as a pictogram, but at least more helpful than nondescript rectangle. This may be why it's the most common one.)
This bit from a driver's manual for a specific state I just pulled up even specifies that this shape is basically only for that:
That sign... It's even worse, since it doesn't respect the international conventions and the text is even less legible 😬
This actually got me curious if Canada and Mexico use different signs since I know several of Canada's signs for sure are very similar to the US (but differ in some ways particularly because Canada designs for a multilingual population, typically French, but also Inuktitut and Cree in some areas). I can't find the Mexican one, but the Canadian one is two cars next to each other with a "no" sign over it. Which is definitely even clearer.
According to this, Mexico has signed the international standard, so it should be different from US & Canada:
(also, the two cars next to each other with a "no" crossline on top is the standard, so Canada may be closer to the Vienna's convention than the US)













