Perhaps a more relevant question might be: are the "Winnipeg City Routes" (Winnipeg, Manitoba, Canada) (canmbw) actually maintained by the province, or by the city? I don't know, but perhaps someone on the forum does, and the answer could be relevant here.
Maintained by the city I believe.
The Winnipeg Routes are a unique case, a one-off; they're the only such numbered/signed city system in Manitoba; it's highly unlikely that there will ever be another in the future. As such, there won't be any confusion with any other potential city systems, or a need the differentiate multiple such systems within Manitoba.
Some quotes from the canbmw thread:
Jim: "These seem to be an unusual case where they are well-signed and seem to take the place, within the Perimeter Highway, of what might normally be expected to be part of the provincial system."
mapcat: "I agree that they're a special case, and not analogous to USA county routes, or other smaller district systems we don't include."
I agree with this assessment. (Of course, having drafted the system.
) I'll note that not only are many of them extensions of canmb/canmbs routes from outside the Perimeter Highway, but many are themselves former Provincial highway alignments.
The canmbw thread blew up a bit too fast, and I've just left it alone for a while, but some day I'd like to revisit it, hash out a few of the topics therein as needed (maybe even with a topic split), and move canmbw toward activation again. But it's a low priority right now.