There's two common motorcyclist signals for police: Either tapping the top of the helmet, or pointing up at the sky while moving your arm in a circle (to mime s

There's two common motorcyclist signals for police: Either tapping the top of the helmet, or pointing up at the sky while moving your arm in a circle (to mime spinning police lights). Other motorcyclist signs are sticking the left leg out to say thanks, holding your hand out and rapidly opening/closing it to say "you've left your indicator on", and pointing at dangerous spots on the ground like potholes, gravel, or other unseen hazards.