My buddy (former cop) says there three things they look for when passing people.
1. Good guy wave.. A simple hand gesture involving a simple raising of the hand slightly off the wheel. just like you'd do with anyone. most likely you're not even looking a the cop.
2. Dumb guy wave. You wave like an idiot and look at the cop to make sure the notice you.. you're likely getting followed or pulled over.
3. Bad guy wave. Not a wave at all, you intentionally hide your face by conveniently looking away at the "right time". You're likely getting followed or pulled over.
