You may have seen this already, but it might still be of interest to those who havent.https://www.indiegogo.com/projects/solar-roadways#home
It's a company called Solar Roadways who have designed a hexagonal solar panel that can be used as a road surface. It can be used to provide different lights, power nearby buildings, release heat to eliminate ice from roads, alert you to animals on the road to name but a few.
As this could be what we drive our minis on in the future, worth a quick look at the least!
Personally, I think it's a class idea and I can see it's potential for safer, efficient roads in the future.