* Red Bank has collected almost $2.2 million in gross revenue from its cameras since 2006.
* That translates to about 44,000 citations.
* Chattanooga has collected $3.5 million in gross revenue from its cameras since 2007.
* That translates to about 70,000 citations.
In the Tennessee Valley, only two cities have adopted photo enforcement of speed limits and red-light laws - Chattanooga and Red Bank.
Chattanooga has 12 sets of speed cameras while three are spread through Red Bank's main thoroughfare, Dayton Boulevard.
Neither police nor traffic engineers will reveal how fast drivers must go to make the cameras flash, but officials warn against pedal-to-the-metal style when "photo enforcement ahead" signs come into view.
Twenty-four hours a day, the cameras record digital images and license plate numbers of violating vehicles at intersections.
After validating the images, police officials send $50 citations to drivers. In Chattanooga and Red Bank, the citations can be appealed in court.
Citations are not moving violations and do not count as points on car insurance policies.
Several residents recently challenged cameras in both cities as part of a $10 million class-action lawsuit, claiming instant photo enforcement penalties infringe upon the constitutional right to due process.
Their efforts stalled when Hamilton County Chancery Court Judge Frank Brown dismissed the lawsuit last October.
Defenders of photo enforcement point to safer roadways and stronger overall surveillance. They cite a March 2010 case in Red Bank in which four home invasion suspects were caught when one the city's traffic cameras caught a license plate on a black Camaro as it sped down Dayton Boulevard.