By Ronni Berke, CNN
New York (CNN) - When a red light camera photographed Terry Williams going through a Santa Monica intersection, she had no idea what had happened. "Pop, flash, and I'm sitting there, and was like - what was that?" she thought.
Williams even thought it might have been gunfire, until she told some friends about her experience. You're about to get a traffic ticket, they told her. Two weeks later, the ticket arrived in the mail.
Although she paid the $380 fine, Williams went to trial to contest the ticket and eventually won her case after an appeal - by demonstrating that there was a traffic light malfunction at that intersection.
Williams says she is especially angry that the initial traffic court judge dismissed photo evidence she presented to support her own case. "She didn't want to hear anything I had to say. I was just guilty," Williams recalled.
Red light and speed traffic cameras seem to be popping up everywhere, saving law enforcement time and manpower and generating millions in revenue for cash-strapped states and municipalities. The cost of a camera citation is decided by state or local authorities.
In Los Angeles, a violation results in a $436 fine. Red light camera citations brought in $3.3 million in revenue in 2007, said Sgt. Matthew MacWillie of the LAPD, co-coordinator with the Los Angeles Dept. of Transportation of the city's red-light camera program. However, the city got less than half of each fine - the rest goes to the state and county.
The red light camera business is growing rapidly, vendors say.
Redflex, the largest vendor of red light cameras, has 1580 red light , speed, or combined red light-speed cameras operating in the United States. In 2008, the company made a net profit of $7.9 million, double the year before, said Cristina Weekes, Executive Vice President of Marketing at Redflex. American Traffic Systems, a Redflex competitor, operates more than 1,000 cameras in the U.S., and is expecting to install 500 more in the next few months.
But some red light camera critics, like Williams, and even lawmakers, are fighting back, saying the devices circumvent due process or even cause more crashes than they prevent. Some drivers are purchasing sprays that claim to block their license plate numbers so cameras can't "read" them. Websites like "highwayrobbery.net" and "cameraSCAN.com" post detailed arguments against the cameras, and some states are even considering banning them.
Georgia state Rep. Barry Loudermilk pushed through a law this year to regulate the use of the cameras in his state. Loudermilk says a better way to reduce accidents is to extend the length of the yellow warning light in traffic lights, by just one second - from the minimum three seconds required by federal law. At the Atlanta intersection of Freedom Parkway at Boulevard, cameras brought in $1.3 million from more than 49,000 in violations last year, Loudermilk said. Atlanta charges $75 per violation.
Loudermilk says some towns in Georgia who put up red light cameras shortened the length of time a light stays yellow to catch more red-light runners. So, he pushed through a law that requires lights in Georgia to stay yellow for a second longer, to more than four seconds.
Since the law took effect in January, at least three Georgia communities have decided to no longer use red light cameras, because they're not "cost effective."
Safety experts like Adrian Lund, President of the Insurance Institute for Highway safety, say red light cameras improve safety at intersections, by serving as a deterrent.
"Our overall position on red light cameras is that they are effective, they are saving lives by preventing people from disobeying the law," Lund told CNN.
Critics say the cameras increase rear-enders, because drivers tend to jam on their breaks trying to avoid a ticket.
Lund admits that after cameras are installed, there is a "smaller" increase in rear-end crashes, but says they are far less deadly than the "t-bone" collisions that occur when a car runs a red light and smashes into the side of a passing car.
And although Lund agrees that extending the yellow light time does have safety advantages, he says longer yellows don't reduce red light running as much as having the cameras installed.
In Los Angeles, Sgt. MacWillie says the camera program has steadily reduced crashes since its introduction in 2006. There have been no fatalities at intersections since the program began.
"If you're measuring the program by the goal - to reduce traffic collisions, it's working," MacWillie said.