As long as they meet power factor specs for various local power companies they'd likely be a nice addition where polycarbonate signals are allowed.
Many jurisdictions only spec cast aluminum. PC is nice and light and costs less but after a few years in the sun and smog they get extremely brittle, especially the thin visors. And the ones with glass-fiber reinforcing sheds the fibers when they get really old and you better wear gloves and eye protection when handling them, especially if the wind is blowing .