@aaroncorsi while I agree that cars should be seen for what they have done to our planet, these paints are neat from a physics perspective. I ran a similar calculation to that in the article a while back and remember immediately concluding that it was absolutely an terrible idea.

That being said, the "space cooling" ultra white paint has interesting applications in urban and rural environments in a warming world, for what it's worth.

@aaroncorsi for sure, just wanted to add context because I find this material interesting.

Roofs are far better (don't want to blind pedestrians and drivers with ultra white paint, our roads are already unsafe enough). The paint can be used for passive cooling structures as well. Think a pavilion with a passive cooling canopy for sub-ambient conditions as a heat refuge without needing to run power. Permanent structures in public square and parks or temporary structures for events in summer.