I think you’ll be unable to change much. :wink:

In case you haven’t already seen it, this wiki page documents how each country tags their highways. Many countries have already decided how they want to tag highways, and you’re probably not going to have much luck in changing their minds. Motorway tagging is probably pretty similar across most countries, but you can find very different tagging for trunk, primary, secondary, and tertiary.

I do see that for Poland, they’ve decided that A class highways should be tagged as motorways, but S class as trunk. If you feel that this doesn’t accurately represent the situation on the ground, you’ll need to discuss the matter with the Polish OSM community and convince them.