As usual, Brian Herzog nails it:

Instead of just using traffic cameras to catch people speeding, they’re using them to also catch people obeying the speed limit – and by following the law, those people earn a chance at winning a share of the revenue generated by speeding tickets. By offering a reward, the police are hoping to encourage more people to drive safely.

The theory, called gamification, is that people enjoy playing games because of the positive reinforcement from doing something well – thus turning something normally punitive, like a speeding fine, into a game of consequences: play badly and get punished, play well and get rewarded.

How awesome would it be to do this with library overdue fines?

It would be even better to arrange the game so that there’s no punishment involved. Only rewarding folks who bring items back in a timely manner.