I think there was an episode of white color car vs black color car when left under the sun. I think the white color car was like 20'f cooler.

On a side note, although I've never seen a black color postal delivery vehicle before, the white color ones I driven at work are awfully blazing hot. Much hotter then outside air temp. It just make me want to rush to my next stop and quickly exit the vehicle.

95 Montero SR