Self-cleaning glass is a fairly mature technology and will work effectively on a rooftop solar installation. That won't work on a solar roadway, which a) needs

Self-cleaning glass is a fairly mature technology and will work effectively on a rooftop solar installation. That won't work on a solar roadway, which a) needs a textured surface to provide adequate grip for vehicles and b) can't retain any sort of coating due to friction and c) is constantly being covered in axle grease, tire rubber, brake dust and the innards of various wild animals. https://en.wikipedia.org/wiki/Self-cleaning_glass https://en.wikipedia.org/wiki/Self-cleaning_glass