Hate to break it to you, but Nelson isn't 'primary' either.  There's no chance it's higher type road than Babcock, Thompson Run or even Perry Highway (US-19).  Especially when there's signage @ McKnight Road that says 'NO THRU TRAFFIC', meaning 0% chance the road is a 'primary' route.

That's why it was originally tagged with 'highway=unclassified' for most of it's distance.  It isn't residential, but unclassified is the next tier above residential, as it isn't a tertiary road either.

I've just re-downgraded the road back to it's proper type.