So, I don't think this is actually a thing. Drove the theoretical route this past week, there are zero shields posted. The closest thing that exists to a sign for it is
this, which... yeah I don't think that counts.
Meanwhile the portion that isn't concurrent with US50 is a narrow residential street (with a posted speed limit of 20!) that according to
NDOT's GIS is owned/maintained by the city of Ely.
Recommend deleting, therefore.