It took me a while to figure out what is the point? Finally I came across an article that cleared it up. Apparently these roads would have stripes which light up, so no paint is required. Lots of Global Warming stuff, so these roads would not radiate heat back into the atmosphere. But the main issue is that they are intended to generate solar energy into the American electric grid replacing oil or coal generated energy.
There is some vague reference to them being programmable, and that they may be able to communicate with futuristic vehicles, although this not really fleshed out as to exactly what they mean. I assume they are referring to driverless vehicles. The concept is vague and untested but anything you can stamp 'Global Warming' on will almost always get government funding. It sounds to me like that is what this is all about.
It is hard to imagine normal traffic, heavy trucks and autos, driving on solar panels without destroying them. But, they think they can do it. Also, it is not clearly explained how they deal with shaded roads, snow covered roads, continuous cloud cover in winter, debris in the road, or roads with perpetual heavy backed up traffic, which would not allow sunlight to reach the panels. Also they would have to be cleaned somehow to clear the rubber coating they will necessarily accumulate from the tires.
All I can say is ... Weird.