"have about as much effect on the tempered glass surfaces as your windshield wipers do on your windshield." And this is where you lose me. Either you've never

"have about as much effect on the tempered glass surfaces as your windshield wipers do on your windshield." And this is where you lose me. Either you've never seen a tempered glass surface, or you've never seen a road, or maybe you just have no idea why roads are built of the things they're built of. Asphalt is a pliant surface made of viscous hydrocarbons and filler that slowly stiffens up over a period of years. You can scratch it, you can embed pebbles in it, you can heat up the center twenty degrees warmer than the edges, you can run a metal snowplow over it, you can press furrows in it until some parts of the road surface have 30 degrees of divergence from other parts of the road surface. To some extent it's self-leveling, balancing out physical distortion in one spot with physical distortion in another spot five seconds later. The way you cut glass (at least, without a specialist sawblade) is by scratching it and then applying pressure. The crack propagates and it shatters into two pieces. This doesn't work with tempered glass at all; The surface is under so much tension that it tends to shatter into many pieces instead of two. Roads don't get scratched as exceptional events - it happens many times a day, with tires, steel bits hanging off, but most problematically, with quartz pebbles (harder than glass) embedded in tires. Go look at your tires; Rub your finger along the surface. Now rub your iPhone along that surface. Melting glass and transporting it in whole sheets is energetically very expensive. Installation is extremely difficult. Wear characteristics are not only unworkable, the glass would rapidly become frosted and translucent. If it was economical to make roads out of glass, we would be doing it. It's not even economical to make them out of concrete except in isolated circumstances. Roadway solar panels are a laughably bad idea. Green inventors are condemnable when they waste our very limited enthusiasm for green ideas on obvious technical nonstarters. I've been watching this space for more than a decade and I'm beginning to despair at the ratio of design/architecture student renders to even back-of-the-envelope engineering effort.