Solar Roadways get prototype funding from DOT

From Autoblog (via Slashdot) Solar Roadways get prototype funding from DOT

I don't see how this could be cost-effective. 5 billion 12' x 12' panels (presumably at less than $100,000 it costs to build the prototype) still has to be pricey (i.e. it would surely be more expensive than a glass window of the same size, so we are talking on the order of $10,000). 5 billion x $10,000 = $500 trillion dollars at a minimum. Mere pocket change, less than my credit limit on my credit cards.