> I'm concerned that any shiny object near a roadway needs to be carefully aimed not to blind drivers

We seem to deal with driving near the ocean and other bodies of water just fine.

Big difference between a large flat reflector 20 feet away, and a uneven ocean surface, likely atleast 100 ft away...

That said, at the right angle, no, its not just fine, the ocean reflects alot of sun, just like anything else.

Not to mention other cars have a lot of shiny surfaces too.

Yes, but curved, not a large flat reflector. Huge difference

About aiming… solar panels want to be installed normal to the sun which means any reflection is going to go back toward the sun. Of course the sun moves around but the reflections are mostly sunward. You’d probably have to have panels in a steep valley to reflect back toward a road.