They hung these all over Springfield, Mo. a few years ago, for red light violations. It was taken to the Missouri Supreme Court. They were deactivated. Appears the court took a dim view of the following.
Quoted from TheNewspaper.com
"The city of Springfield, Missouri prepared for the installation of a red light camera system by slashing the yellow warning time by one second at 105 state-owned intersection signals across the city. In a 2005 Texas Transportation Institute study, a one-second reduction in yellow time resulted in a 100% increase in the number of violations (Table 6-2). Each violation under Springfield's new system will bring a $100 fine to city coffers after ticketing begins on June 1."