It's All About Revenue
Wonder why some traffic signals' yellow lights seem to blink to red a lot quicker than others? Chances are, the traffic signal is equipped with a camera system that automatically photographs red-light runners and mails them a ticket. Shorter yellow lights means more violators - and more revenue. It's all about the bucks. You have 'em. Government wants 'em - and they're willing to put your safety at risk to get them.

These kind of cameras are already operating in Tennessee - in September 2002, the Memphis suburb of Germantown became the first Tennessee municipality to install them. Soon, they'll be everywhere. Incidentally, according to this roundup from the National Council of State Legislatures, Tennessee apparently has no laws on the books regulating the use of such cameras - no laws to prevent, for example, your local revenue-hungry police department from shortening the yellow-light duration to maximize the number of tickets issued to drivers for running the red light.