This specific venture is an outstanding sample of wasting taxpayer bucks on outrageous stuff. While almost every engineer who has a chunk of paper and a pen expected the inefficiency of Solar Highway, the eurocrats proceeded to waste taxpayer money vigorously.
We now have commercial installations of solar arrays all around the world, and we understand that they are still expensive when compared with some other energy sources. The solar panels are aligned with the Sun to attain better performance. They are usually washed regularly, get a lot of repairs and maintenance, and no-one is going to damage these with a few tons of mass. That's the reason the solar highways will never be so profitable as solar powered energy stations. The solar highway can't be aligned with the Sun, and it often will be shadowed by cars and trucks! It's so damn predictable!
One other useless idea is using technology in attempts to produce the solar highway damage proof. The highway construction industry improved the cost effectiveness for hundreds of years. Renewing the road coating with pricey solar panels will ruin the ROI for both: the road itself and solar energy projects.
I highly doubt that such solar roads will be a part of the nearest future. Regardless of how much money is going to be invested in scientific studies and how many freshly ground coffees cups the engineers will probably drink.
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