Reflection color depends on the environment and the material, For example, the reason that car reflects mostly white is because it is in a white room with a high gloss value on the paint, but not all paints are glossy and we aren't always in a flat colored room.
Painted metals in particular can actually vary by a large margin, but the paint generally reflects less of the world color than the metal itself.
Example with point lighting, a good approximation of a flat colored room:
Example using image based light:
HDR with lens flares:
As you can see, the metal and paint have similar albedo values, with the metal being slightly darker, however the metal has a very light gray specular color, while the paint has a dark black color. The gloss shows similar values for the metal and the paint, with the metal being slightly lighter overall. Using the HDR with lens flares, we can see that the metal tends to reflect more light than the paint.
Just some interesting insight into how PBR should look.