Now, I know that the fact that this is apparently unsigned is a striket against including it (https://en.wikipedia.org/wiki/North_Carolina_Highway_581#Goldsboro_connector), but take a look at the map around Goldsboro. Between the southern end of I-795 and NC581, we have a bit of freeway that isn't clinchable in the database. That should be included, and I think we can overlook the unsigned nature of this short segment. Thoughts?
We have a route set that is home to freeways with no signed route numbers. That's where we put Florida's Turnpike, for example, as well as some shorter freeways. But not as short as the NC 581 Connector, only 0.8 mile long.
In North America, numbered routes known to be unsigned are really rare in our database. I think the exceptions are all far longer than NC 581 Connector. They also are only in our Arctic jurisdictions, where signage customs are different than in the lower 48, and even on a signed route you can easily drive more than 100 miles without seeing any route number signage.