Well, that's a good point about the connection between Bethesda (or DC) and Poolesville, but Poolesville is a small town at best and more like a large neighborhood.  I think the highway importance ratings in general need more consideration in this area.    The description for  “primary” is “connecting large towns/cities”, which Poolesville is not.  “Secondary” is lesser and “forming a link in the national route network”.   “tertiary” are “county roads and main connector roads through neighborhoods”.   Seneca road simply connects old Darnestown to the town of Seneca (which no longer exists).  I would tend towards “unclassified” for Seneca Road, but can entertain an argument for “tertiary”.   I see Esworthy as a neighborhood road with driveways every 100 feet or so that gets significant through traffic (River to 28), so maybe call it tertiary.  The northern half of Seneca is about the same as Esworthy.  The southern half could be “unclassified” but let’s call it “tertiary”.  River from Esworthy to Seneca is even less significant.  Does this make sense to anyone else?