Road paint is latex paint, so the first step is to try latex paint remover, follow the manufactures instructions.
Step2
If the latex paint remover fails to remove the paint take a look at the thickness of the paint. Is it really thick? If so you may want to try peeling the paint off using a plastic razor blade.
Step3
For thinner splashes of paint try rubbing it off with rubbing compound and a sponge.
Tips & Warnings
Removing road paint is not easy. If the above does not work, you may need to take your car to a professional detail shop in order to get rid of the paint without damaging your vehicle.