You are from Wikipedistan?
Seriously though, we had a badly insulated district heating pipe under the sidewalk across the street. Net result? No need to plow or grit unless in loads of snow/really cold :lol:
All our heating pipes are in the ground, in order for them to freeze up they would have to break down for weeks before getting that cold - in that case the weeks-long breakdown would be the bigger problem.
There even is a 5m-diameter 1.4km long tunnel under the fjord to supply the west coast with tasty heat directly, 130?C in the winter and 70?C in the summer.