Leave it to California: the California Air Resources Board is trying to figure out how to cool your car so that you don't have to waste as much fuel on AC.
The idea is to keep the car from getting seatbelt-burning-into-my-flesh hot in the first place. There are three proposed methods:
solar cooling paint, solar ventilation, and reflective window glazing.
I can imagine that this would have a huge impact- running the ac in my old car meant that my gas mileage went way down. Wonder if this is yet another experiment that has its start in CA and eventually becomes nationally mandated.