America can't even keep normal asphalt from turning into a giant coast to coast pothole with occasional pavement at the moment, so I have my doubts. Then again, I haven't studied the numbers - even today, though, the cost for America to maintain roads is something like $125 billion a year and that's clearly not nearly enough from what I can gather, what with 70000 structurally deficient bridges at the moment and so on. There are some downsides to blowing over 50% of the federal budget on war-related activities.
It would be interesting to see numbers on how much this would affect maintenance. If repairing roads would be just a matter of quickly laying down fresh hexagonal solar roadway pieces, the savings over time plus the energy derived from them might actually work out to something usable.
Power itself can be had more sanely, like by building thermal solar powerplants in the deserts and piping the electricity to where it needs to go with high-voltage direct current super grids, but the side benefits of the solar roadways - melting roads clear, keeping walkways and such free of snow, laying down cable channels along every road to eliminate the utterly archaic air lines that America is still using (see "spending 50% of the federal budget on war related activities" again...)
Well, just because it initially seems very counter-intuitive and expensive doesn't have to mean it is. I'd have to see real numbers crunched on it.
Personally, I think the best (if sad for us riders) solutions for transportation into the future will be maglev rail, not roads at all. Much more efficient, faster and lower maintenance on the rail since the trains float over it, instead of grind down into it like vehicles do on roads.