Washington, DC, put up red light cameras as a public/private endeavor some time ago. The deal was to split the resulting fines between the city government and the private company that installed and maintained the cameras. But the company shortened the yellow light cycle by half a second, if I remember right, and that alone caused an enormous increase in the number of fines and the amount of money they made.
The British did a similar scheme, installing red light cameras in most metropolitan intersections. We'd regard it as an Orwellian intrusion, yet they claim it helped to reduce traffic fatalities by 40%. Here in the US, that would be about 16,000 people per year.
http://www.chicagotribune.com/news/local/breaking/chi-charges-filed-against-former-city-hall-manager-of-redlight-camera-program-20140514,0,1982915.story