Coarse gravel is sized to model gravel roads more realistically.
Use accent powder for shoulders and to model bare spots on roads.
Coverage:
Gravel 10.8 in3 (176 cm3)
Accent Powder 1.8 in3 (29.4 cm3)
Models a gravel road 14' x 2" (4.26 m x 5.08 cm)
Actual coverage depends on usage.