I heard a story about a new idea: gamifying speed cameras:
Apparently, in Sweden they have tried this. Instead of the money collected from speed cameras going to the government, the profits go into a lottery. The lottery winners are selected from the people who drove by the speed camera at or below the speed limit. The way it works is that the cameras not only take pictures of speeders; they also take pictures of everyone going at or below the speed limit. The story said that it has been quite successful in Sweden.