Eventually all of the rural roads (less than state highway status) get some type of seal coat here in Wisconsin. Initially the loose material is a real hazzard at the edge of the road and intersections. In my area they often used crushed basalt which can have some very sharp pieces. Historically most of my flats come on relatively fresh coatings of this type. The small rounded pea gravel can be looser to ride on at first but at least it isn't sharp.