What does it mean when a motorcyclist taps his helmet?

What does it mean when a motorcyclist taps his helmet?

High Beams On—When a rider taps their head, it is usually to indicate that high beams are on. In some groups, it can be used to mean that there are cops ahead. Debris on Road—If a rider shakes his leg, it is usually meant to tell the riders behind him that there is debris coming up ahead on that side of the road. Feb 18, 2014