Say you’re zooming down the highway, when you spot one of those speed-limit enforcement cameras from the corner of your eye. You hit the brakes, but not before the camera’s flash catches you breaking the law. A speeding ticket is surely on its way to your mailbox.
A car passes a warning sign for speed cameras.
Now, imagine that same camera also snaps a photo of your car when you are driving at or under the speed limit. For your safe driving, you are entered into a lottery to win a portion of the money from fines paid by speeders.