Though useful it can be argued that most traffic enforcement type can be categorized as revenue enhancement. Having known a number of police officers and a few police chiefs the concept of increasing a departments operating deposits by citations is a very common one. Often such enforcement is in areas of few accidents but where speed limits transition and catch people unaware or are inordinately slow for a given area. There are exceptions of course.
This is no slam to the officers. It is decided on a local political level and you do what you are told to do if you want to keep your job. Placing electronic traffic monitoring/enforcement devices in England for example has made imperceptible statistical differences in accidents and fatalities in most areas. They were so costly to maintain that with the public’s knowledge were shut off without an increase in accidents. For me though the whole Orwellian thing of a perfectly monitored and centrally controlled society (1984) is a bit creepy.
By the way, I think what one poster meant was that you can shape public opinion and/or get the answer you're looking for simply by how you present the question.