It's late at night as you drive home. Suddenly, you notice flashing blue lights behind you. A police stop? Were you speeding? Did you fail to yield? Or perhaps you accidentally ran a red light? You pull over to the side of the road, and a police officer steps out of her patrol car. She walks up to your window and motions for you to roll it down. Good evening, she says. Any idea why I'm pulling you over tonight?