Solar roadways promised almost everything… they would stay up for you when you got home late at night, they would take out the trash and cry when you got split ends. However in the end, after about 2mn dollars of government money, and 2mn dollars from an indiegogo campaign, they delivered on basically nothing. Their installation current generates no energy because its covered in snow, but even if it wasnt it would be generating about 1 cent of electricity per day! Even when it was at its prime, in the middle of summer it generated about 1/10th the power it would have if those solar panels had been put in a normal rooftop installation.
Even professionally done versions of this concept are simply non-starters, like the Colas wattway. The Chinese also recently announced they had built something similar.
EEVBlogs did quite a nice breakdown of it.
You can support videos like this through patreon