https://wiki.openstreetmap.org/wiki/Tag:highway%3Dunclassified
In some countries, unclassified roads may be unpaved in larger, poorer or more remote/rural areas, and are typically paved in denser, richer or more central/urban areas. In this case, you should add a surface=* tag to indicate the surface.
Я расставил surface= на тех местах, которые успел заметить во время поездки туда.