A new neighborhood without official roads?

This morning I ran around construction site of a new neighborhood in Pahrump, Nevada where they already laid out the outline of the roads.

Obviously it’s not updated in OSM yet, but I wonder when it is, someday, whether my run will count automatically.

I assume so, otherwise I need to know whether I need to re-run it again when it’s completed and updated with nodes?

The answer is yes, when the roads are added. If you have experience in OSM you can even add lines where the roads are, there is a class of way called “road under construction” which would allow you to put the road names now if you have access to them from a planning site, or if the street signs are already up.