Fair point. It’s true that using a combination of several tags borrowed from cycleway, you can capture all of this complexity. separation and traffic_mode can perhaps be used verbatim, but cycleway itself, which captures some important information too, obviously can’t be used. A tramway tag could have shared (with cars), lane (on the road but exclusive for trams) and light_rail (off the road) options, though only lane needs separation and traffic_mode.