LONG BEACH, N.Y. — A symphony of bleeps inside the police cruiser drowned out nearby traffic on a recent morning as Sgt. Bill Dodge pulled into a public parking lot. The pace of the bleeps quickened when he passed the first row of cars.
"There's nothing in here," Dodge said. "Let's head out into the street."
Turning into traffic on Beech Street, Dodge passed dozens of cars before the bleeps gave way to an alarm, then a robotic voice telling him about a parked van whose registered driver has a suspended license.
"It just did in 30 seconds what usually takes an officer an entire day," he said.
New York's Long Beach Police Department is among a growing number of law enforcement agencies using the roof-mounted license-plate reader, the Mobile Plate Hunter.
Bleeps and alarms are emitted as the device's two infrared cameras scan license plates at a rate of 15 to 25 a second, said North Carolina-based manufacturer Remington Elsag.
Those plate numbers are sent to a database in the police car trunk and compared with a digital list of vehicles wanted for crimes, traffic violations, reported stolen cars and vehicles linked to alerts for kidnapped children, authorities said.
The infrared cameras, which work like supermarket scanners, can record the plates of moving or stopped cars.
Such systems are more widely used in Europe.
"We live in a post-9/11 world," Remington Elsag President Mark Windover said. "When you look at many domestic terrorism incidents, many times, a vehicle is involved."
More than 220 departments nationwide use the $22,000 machine, according to the company.
The New York Civil Liberties Union sees potential problems.
The group opposes a New York City proposal called the Ring of Steel that would feature a similar license-plate recognition system. That plan calls for infrared cameras to scan plates of Manhattan's inbound traffic as part of anti-terrorism efforts.
"From our perspective, police should be in the business of investigating crimes, not tracking law-abiding citizens," said Christopher Dunn, the group's associate legal director.
Driving is a privilege, not a fundamental right, Dodge said, adding that officers have always recorded plate numbers for investigations. The reader, he said, makes that work easier.
In Arizona, Gov. Janet Napolitano said the device was helping to combat human trafficking. Because smugglers often use stolen cars, her spokeswoman said, cruisers equipped with readers at the border can help break up trafficking rings.