I’m sure most of you are familiar with a Radiometer. When placed in a source of light, the vanes will turn in a direction that shows that the force on the dark surface is larger than that on the white surface. The direction of rotation is attributed to the greater heating of the black surface over the white. So with that fact, if your rear bumper was black and your front bumper was white, science supports the idea that you will go faster as long as you’re driving during the day. Driving at night you will gain no advantage, everyone will be on a level playing field.