This is really cool. What do you think the remaining ~1% is?

Some counties haven't digitized their maps, some require I go see them in person. There's one in particular that wants me to mail them a check for $10,000. Haven't done that yet...

The area inside the circles described by cloverleaf interchanges. ;)

Coverage is calculated by actual / expected # of parcels, not area. But good try :)