If you want solar roadways, the actual solution is to build a canopy over the roadway so that you can get direct access to the sun, but even that has a million logistical problems that make it a nightmare that simply isn't worth thinking about.
For instance, what happens when a semi truck plows through a pole holding part of the canopy up? What is the shutdown procedure for the system in that event, bearing in mind of course that you cant actually shut solar panels off. If they have access to light, they're active. Solar panels can be made semi transparent, but you're still dealing with reduced light conditions on the road surface, and reducing the efficiency of the panels if you do that.
The real problem is that these types of projects are trying to solve a problem that doesn't actually exist, and are doing it in a way that is staggeringly ineffective, expensive, and nonresident. Real estate is cheap. Put up your generation source in a sane location, step the voltages up to the millions to reduce transmission losses, and run high voltage lines across the country. You know, like we already do that with every other source of power generation because it's orders of magnitude cheaper?
Or just stop being fucking eco yuppies and embrace the real green solution that can meet demand irrespective of whether the wind is blowing or the sun is out. Embrace nuclear. Most of the plants in the world are so out of date it's not even funny, and brainlet eco freaks are to blame for that. You can't just make the wind blow when you need more power. You can crank up a nuclear reactor to meet demand, especially the modern ones which can adapt to loads very fast.