I started to think about the folding up thing. And I think it makes it worse. Considering things like long time reliability. There is fact that you somehow need to connect those panels electrically. Just considering various potential water ingress issues when driving in rain at high speed. Yes, you can make water-resistant connections, but them correctly operating over years...

And next is vibrations, from cross-winds, bumps in road or traveling over uneven surfaces. Adding up over longer periods.

Not to even mention possible wear and tear of spreading them possibly everyday or multiple times in a day... And for bonus, at least here there is periods where mud is relatively common so this will travel in mechanism making it harder to operate...

I would be worried about long term reliability and usability.