Official classification of highways

Hello, in order to allow for a more consistent usage of highway=*, I’d like to propose global tagging of the official, national highway classification. In some countries, highway=* already corresponds to the official classification, but that’s not the case everywhere. Now, ref=* usually already shows what the road is classified as but sometimes roads can have no ref and in that case, noref=* doesn’t give any information. Sometimes, at junctions, roads can have small sections of no ref but sti...