We had a red light camera on one intersection in my city for a number of years. The city fathers installed this camera for "safety" because of so many people were jumping red lights at this intersection. Despite this being the only red light camera in town, being clearly marked by signs and well known to the public, the number of red light jumpers and the amount of fines always seemed in increase each year. There was absolutely no deterrent effect. Fines were shared by the private Arizona company that owned and operated the red light camera and the city. The company also controlled the timing of that stoplight.
While our state legislature finally outlawed red light cameras, there was always a suspicion that the company was deliberately shortening the time of the yellow light to increase revenues.