The pathway to hell is paved with good intentions.
Surveillance cameras designed to catch red light runners have a significant back-fire effect: Driver fear of getting tickets by racing through the yellow causes more people to slam on their brakes at the last minute. Result: More traffic accidents overall, not fewer. Popular Mechanics:
Likewise, red-light cameras in Portland, Ore., produced a 140 percent increase in rear-end collisions at monitored intersections, and a study by the Virginia Transportation Research Council found that although red-light cameras decreased collisions resulting from people running traffic lights, they significantly increased accidents overall.
It gets better: Because traffic light surveillance is a huge revenue opportunity for cities ($32 million in revenues for Washington DC alone), and because people tend to have more violations when yellow lights are shorter, there is suddenly a financial incentive to decrease the yellow light duration. City planners tempted with Faustian deal: More revenue at the expense of more accidents. What red-blooded mayor could resist? One Maryland area apparently saw yellow light durations in one area drop from 4 to 2.7 seconds after installing light surveillance. Imagine that.