my moonbat RSS feeds pushed this my way.
I said "WTF"? how much would it cost? what about surface roughness to prevent skidding? durability, years? decades? maintenance costs? scratching of the surface by road wear that blocks light?
And the above-all-WTF, USA's continent is hardly populated, with Ms of acres of vacant land, esp in the useless, sterile semi-desert, desert from San Antonio to San Diego being available for massive solar panel farms.
Want to get double use of land used for highways while reducing oil consumption? Build elevated railways for high-speed, fully electrified trains (no diesel-electric kludge).