Last month, Baltimore County became the sixth Maryland jurisdiction to deploy an automatic camera system against red-light runners. The system, also used in New York City, is run jointly by local police and the Herndon-based government systems group of information technology company EDS.

It's scheduled to be up and running at some intersections in mid-October. Eventually, 40 intersections in the county will use the technology. EDS's contract is guaranteed for one year with five, one-year options -- worth about $1.2 million a year to the company. All of that will be paid for with revenue generated by red-light violators.

Here's how it works:

1. Vehicle approaches wired intersection. Note to drivers: If you see a 10- to 12-foot pole topped with a metal box, beware. Unlike a traffic cop at a speed trap, the structures are meant to be visible. "Law enforcement wants you to see these things," said Jack Fleming, who oversees red-light programs for EDS. "They are meant as deterrents."

2. Each lane has two clumps of electromagnetic loops buried below the road surface just before the intersection. These use changes in the electromagnetic field to sense passing vehicles. If a vehicle crosses the loops when the light is red, it activates a small camera sitting atop the nearby pole.

3. As the vehicle is about to enter the intersection, the camera takes a photo; it takes a second one while the vehicle is actually in the intersection. The camera is positioned to show the color of the light.

4. From midnight to 8 a.m., an EDS official (or subcontractor) collects 100-foot rolls of film from the cameras. They then view the film and eliminate photos of vehicles that can run red lights legally -- for instance, ambulances, fire engines, or cars in a funeral procession. They also throw out photos in which the license plate is obscured. The keepers are then sent to the appropriate law enforcement office.

5. Owners of the vehicles usually receive $75 citations in the mail within a few days, complete with two photos of the vehicle in the act and a close-up of the license plate. The photos include the incident location, time and date, and how fast the car was going. Fleming said motorists are far less likely to contest photo-generated tickets than ones issued the old-fashioned way. "It's pretty hard to argue against these things," he said. About 90 percent of those contested are upheld in court, he said.

Because the driver of the vehicle is not identified, these citations do not result in points on licenses.