Isn't that a moot point? It can't be done cheaply and efficiently which is why it is not done to begin with. That shouldn't need explaining.
I mean seriously.. its a cartoon video.
Solar has been the next big thing for decades and still is not here yet. Obama, your lord and savior, funded a few solar companies with the stimulus plan which promptly went out of business. The largest I believe was Abound Energy which received over $400,000,000.00 USD and then promptly went out of business and auctioned its assets.
Further, if it could be done cheaply and safely, it would be infinitely easier to implement it on home and commercial buildings anyway. Things that are accessible, do not cause traffic issues to repair or maintain, which are not surfaces affected by freezing and heat and constantly buckling and heaving and breaking apart, surfaces which don't require massive snow plows being scraped over them and which also cover a massive amount of surface area and so on and so on and so on and so on. It would seem quite obvious to anyone that spent even a few seconds thinking about it, that coating road surfaces with something like this is an insane idea... car accidents ripping it up, constant car fires melting and destroying them (yes, if you pay attention on any major highway, there are places all over the place where cars burned), crazy weather, snow, ice, remoteness etc etc etc etc etc. Maintenance itself would be impossible. Further, if there was any surface better than asphalt or concrete it would be in use already. Thinking a solar panel is somehow going to be just fine as a highways surface is a bit silly.... given the fact that the world has been struggling with the "better, safer road surface" question for a century.... and still are stuck with asphalt and concrete.
Furthermore, there is another point which should be fairly obvious. The nations entire infrastructure is crumbling. We have 10's of 1000's of miles of bridges which are not just in dire need of repair, but much of which are beyond repair. So it's not very clear where anyone thinks the many hundreds and billions of dollars just to start something like this is going to come from, when roads and bridges are already falling apart.
Example:
U.S. has 63,000 bridges that need significant repairs
even the crazy schizophrenic above gets it.