> 'a paved surface for vehicular use' The author is assuming that all "restricted access" roads are unpaved, which I think is unlikely to be true. I wonder if

> 'a paved surface for vehicular use' The author is assuming that all "restricted access" roads are unpaved, which I think is unlikely to be true. I wonder if there's data about which roads are paved. Regardless, very interesting stuff, and great analysis.