This is true. I often will plan out a route and If I'm not familiar with the roads, will use either Google maps satellite view or Google Earth, to zoom in to try determine road surface. One clue to look for is on pavement the local hwy. department will often times paint a center yellow as well as side of road white lane markings, which can be seen in the photos. Dirt and gravel never have these, though sometimes asphalt doesn't either.