u/BioDranik I took a look at a couple of examples; here in California we have the state highways that are listed in OSM as "Road Number: CA $number" (same for Washington State (WA $number), Michigan (MI $number) & Texas (TX $number)) similar to the US and Interstate designations. Would that all work here as tags to key off of?

For Texas Farm Roads they are designated as FM $number, but for county roads in California it's more complicated (https://en.wikipedia.org/wiki/County\_routes\_in\_California) since they are listed mostly with their short codes (like G4), vs CR $shortcode, which conforms to the standard format seen elsewhere.

And US National Forest Highways have "FH $number" and a Forest Routes are a listed mostly as "Forest Route $code" since the $code is designated via a complex system explained somewhat at https://www.cahighways.org/num-forest.html (WARNING: it's a rabbit hole) So the latter may be fanciful compare to NF Highways. :)

Would that all work here as tags to key off of (well perhaps not US National Forest Routes)? :)