@ Allexxander - Red pigments are inevitably based on iron oxide. Guess what iron oxide likes to do? That's right: oxidize some more. It's also known as rust. It's a very unstable compound and has no business in a car paint. Except that it looks so good. ;-)
Red paint reflects red light.
It therefore absorbs blue, green, UV etc light.
The shorter wavelengths of light have greater energy and cause more "bleaching" of the pigments in the paint than the other colours.
Therefore it fades quicker.
Red's more noticeable than other colours when it's faded.
