For those who don’t know what is the subject about:
In Russia we came to a question on how to map winter roads, that are entirely impassable during summer. Since Russia and Canada are the only countries that have winter roads, I decided to ask your opinion.
In wiki we can find only mention of ice roads, which are built upon water basins:
Wiki suggests to mark this status in surface=.
It is clear, that value of the new tag should be “winter_road”. But the question is which tag to use? If we put it into surface=, and keep any standard highway= tag (e.g. tertiary, unclassified), then routing will be calculcated via winter and ice roads, and this is a unacceptable in summer. Putting it into highway= tag seems bogus, too.
Opinions? My humble one is: put it into surface, but teach most routing software to avoid them or warn.