Covering the interstate with solar panels doesn't really seem feasible, and I doubt there's going to be enough people in support of cutting down more trees to put in solar. At the moment solar makes the most sense for people putting it on their roof, assuming they have good location / roof angle and the $$$ to install.

Maybe we could generate clean electricity elsewhere where it's more practical and just bring the power in with new transmission lines /s

Don't underestimate how much some people hate change: Displeasure with solar projects at Interstate 95 interchanges prompts Augusta officials to seek additional regulations