[adouglas]

dfox, it's very rare in New England, possibly because our weather is so variable… more often seen in warmer climates. I've run into it in NY state (Orange County) but never seen it in any of the NE states.

It's not the same stuff they patch potholes with. It's literally the same kind of gravel you see used for gravel driveways spread over the surface, and then sprayed with hot tar. Passing traffic mashes it down and you eventually wind up with a reasonably good surface. But until that happens the gravel stays loose. I try to avoid it whenever possible until it's fully weathered in.