Q:
A: Yellow and Red are actually the fastest colours... Also the White cars with those Blue lights on top are quite fast.... However to answer your question , Black is faster by keeping the air near the surface warmer, it reduces the viscosity of the air in the boundary layer. This reduces drag, like shaving your legs....but then again it depends on the type of paint , carbon based paints are faster than metallic , lead based paints.. its all to do with thermodynamics and metallurgy..