This project is a great sample of spending budget on ridiculous things. When almost every engineer who has a piece of paper and a pencil expected the ineffectiveness of Solar Road, the eurocrats continued to waste taxpayer money zealously.
We have commercialized installments of solar cells world wide, and we understand that they are still expensive compared to other energy sources. The solar arrays are aligned with the Sun to obtain more efficiency. They are usually washed regularly, get a lot of repairs and maintenance, and nobody is going to damage any of them with several tons of mass. This is why the solar roadways will never be so effective as solar powered energy stations. The solar highway may not be aligned with the Sun, and it usually will be shadowed by vehicles! It is so damn foreseeable!
Second ridiculous idea is to use tech in attempts to make the solar roadway enabled to withstand the damage. The highway engineering companies spent hundreds of years in cost efficiency optimization. Changing the highway coat with costly solar boards will ruin the ROI for each of them: the highway and the solar energy project.
I highly doubt that such solar roads are going to be a part of the nearest future. No matter the amount of money is going to be invested in research and the number of coffees mugs the technical engineers will drink.
More reading about this epic fail at thelocal.fr