When I first read about Solar Roadways—super-tough solar panels with built-in LED signs designed to turn roads into power plants—I thought that they were never going to happen. Well, here's a prototype. [Solar Roadways via GadgetReview]
Hardened glass on the roadways? Not only would you have marginal traction in rain or once some oil got on it, but all it would take is one overloaded semi driving over it to make for some unhappy motorists and some (more) dangerous driving conditions. Not only that, but hardened glass will chip over time from road debris and stress point will begin to form.