^
No, not really. We have solar and it's certainly not cheap. It was 40 grand just for the panels on the roof. I didn't fully read the article so I can't say what type of solar they are looking into and which roads they intend to use it on, but a project like this (over 90% of the roads in America) could easily cost well over a couple hundred billion. Which, with electricity at ~10cents per kWh, (or at least around where I live, just under DC) The government would be losing their asses on the deal. Furthermore, The maintanence that the panels would require from tire wear would also have to be factored in. Plus the cost of removing and replacing the panels everytime it came for repaving the road. And top it all of, the casualties that could be suffered because of the low-friction design solar panels have.
Trust me, I'm all for the idea because I think solar is the way to go. But it's just not practical for roadways.
EDIT: I did find the time to read the article and I am quite impressed. However, the cost issues stands.