Red light cameras, for example have been shown to lead to an increase in accidents at the intersections where they get installed.
This is true. The Federal Highway Administration found that red-light cameras increase rear-end collisions but reduce more severe right-angle collisions, saving $50,000 in collisions per intersection per year in medical and repair costs.
Here's how to fix the increase in fender benders. Yellow lights timings are set to give you one second to react, plus enough time to slow to a stop or proceed through the intersection on the yellow. When you're speeding, you have less time to react and must brake harder or blow the red. If intersections with red light cameras also had speed cameras, people would no longer speed through those intersections and therefore wouldn't need to brake so hard when the light changes. As a result, there would be fewer rear-end collisions.
Of course the best solution of all is to eliminate traffic signals and their associated red-light cameras, and switch to roundabouts which not only can handle greater volumes of traffic more efficiently than signals but also result in a 37 percent reduction in overall collisions, a 75 percent reduction in injury collisions, a 90 percent reduction in fatality collisions, and a 40 percent reduction in pedestrian collisions.