Flashing your vehicle lights to warn other drivers of upcoming police speed traps.

A nice gesture so that other drivers don't have to pay speeding fines.

A reminder for people to slow down while driving.

Note: If ya get the signal just smile and wave back :)

When you think up something brilliantly righteous while baked.

a term used on social media for posts that contain flashing lights or flashing pictures and is used as a warning for people who can't handle it or who have mental illnesses because it could trigger seizures for them etc..