Hey a heads up that the surface=fine_gravel vs surface=gravel situation is a little bit sticky in OSM. My understanding is that originally gravel meant more like fist-sized and larger stones, (not the way we Americans use that word) and fine_gravel is more what we typically mean when we say gravel.

But, lots of people have been using gravel to mean any type of crushed-stone surface, so it's up in the air. Just wanted to let you know that possibly fine_gravel is a less ambiguous option for surface tags. Thanks for all your contributions!