NVDB

Sweden

This is an acronym for "Nationella Väg DataBasen" a swedish road database, read more at: https://www.trafikverket.se/tjanster/system-och-verktyg/data/Nationell-vagdatabas/

It is available as "Trafikverket Road Network" in both iD and JOSM and can freely be used to draw from.

There is an manual import project going on if you want to help: Import/Catalogue/Sweden highway import

Speedlimit colors

Definition of the colors in the extra options overlay "Hastighetsgränser" in JOSM. Source

Norway

In Norway NVDB is "Nasjonal vegdatabank". https://www.vegvesen.no/fag/teknologi/nasjonal-vegdatabank/

Some elements in OSM will have a nvdb:id that corresponds to the NDVB database. This aids in updating some values for the element.