This is my least favorite road surface for walking. I’ve only run into it a few times, so it’s no big deal. But man, it hurts to walk on. I suspect it’s the cheapest surfacing option — let’s just lay down some tar and throw some rocks on it. It’s used mostly on lightly-trafficked country roads. It hurts to walk on because it’s one layer of rocks on top of an unforgiving surface, so the rocks push into the soles of my feet. Thank god I only run into this occasionally.