Cruiser-Top Cameras Make Police Work a Snap

In most cases, police do not tell the people being pulled over that a machine, not an officer, ran their tags, officials said. Unless, of course, the person being pulled over asks, "Did I do anything wrong for you to run my tag?" Cox said.

But to Cox, the mobile plate hunter, as it is sometimes called, is more fair than he is.

"It runs everyone that gets within its camera view," he said.

On a recent afternoon, Cox demonstrated how the tag reader technology works. In just a few hours on patrol, the cameras ran more than 1,600 license plates, allowing him to issue two warnings and the $140 ticket.

Every few seconds in Cox's unmarked car, the computer screen beeps at him. A license plate number, caught on camera, appears with information about the vehicle it is attached to. When there's a problem with the plate number, the screen turns red. When a stolen car is located, the reader makes a noise like a machine gun.

Sometimes, Cox just sits in his stopped car, letting traffic pass him. Other times, he cruises along, waiting for a hit he is sure will come.

"Cadillac. Vehicle emissions. See how fast something happens?" Cox said, flipping on his cruiser lights to pull over the Cadillac as his screen flashes red.

Most of the tag readers in Maryland, which cost about $25,000 a unit, are paid for by the Maryland Vehicle Theft Prevention Council, a state organization dedicated to reducing auto theft. The council has purchased seven for the state police, seven for Prince George's County police and at least one for every other county between Harford and Charles -- save Howard, which bought its own, said W. Ray Presley, the council's executive director.

D.C. police have 10 tag readers, and they are used to find stolen cars and catch parking scofflaws. The Virginia State Police have five, though they only recently started using one on routine patrol, spokeswoman Corinne Geller said. The rest have been used in special operations, she said.

Police say there is no question that the tag readers are worth the expense. Prince George's police recovered 400 cars last year using the readers, equal to about $3.7 million, said Maj. Robert Liberati of the county's patrol enforcement division.

Charles County police have recovered 69 stolen vehicles and made 29 arrests in the 1 1/2 years since the sheriff's office began using a tag reader, said Charles Baker, senior detective in the auto theft unit. He said he likes the tool because it allows him to keep his eyes on the road instead of wasting time punching license plate numbers into a computer.

"I just think it makes us a lot more effective and a lot more efficient in how our time is being used," he said. "You can do three to four thousand [license plates] a day with that."

Although police and civil liberties attorneys debate the merits of running that volume of plates, there is one point no one disputes: It is only a matter of time before the tag readers are replaced by more sophisticated technology.

"It's a glimpse into the future," said Steinhardt, of the ACLU. "It won't take long before these things become pervasive, and the one thing we know about technology is it gets more advanced and cheaper as time goes on."