I see it as a polite way to redirect the conversation. I usually respond similarly -- although not that exact wording. From what I can tell it's never agitated the cop, and they've never insisted that I answer their question. They just move on with the traffic stop. Sometimes I get a ticket, sometimes I don't.

So how do you answer the cop's question(s) politely such they even let you go?

You don't. If they want to give you a ticket, you're getting a ticket. If they want to let you off, they'll let you off. If they want to drag you out of your car and beat you half to death, you're getting beaten half to death. The only thing you can possibly do is make the situation worse. Police are the violence arm of the state. You're not in control, and your rights, along with your life, depend on their whim.

> Police are the violence arm of the state.

It should be stressed that it's not so in every country