It's not just for commercial buildings, it's requested by fire departments for homes too, and it's in the international fire code https://www.solarpowerworldonline.com/2018/04/know-your-code...

I agree that you could argue a garage should get an exemption if it's under X height and surface area. But otherwise, it seems like a sensible request.

Too bad, I was hoping solar garages and solar car ports would take over the world... Maybe if you build the roof out of structural solar panels.