Ferreting Out Meter Feeders

Another system under evaluation does the same task by recording vehicle size, shape and color instead of license plates.

The daily battle for weekday street parking, which requires cunning, dedication, timing, experience and sheer luck, often starts before dawn.

Howland said overtime parking has become a huge issue, with thousands of complaints in the timed residential zones and worries about meter feeding downtown.

But the District is just starting to evaluate how such a system would work and is comparing the technology of three firms, Howland said last week. Actual testing is set to start next month. A spokeswoman said she did not know the cost of each unit or how many the department might buy.

On Friday, public works officials showed off a parking enforcement vehicle equipped with a system designed by a Canadian company, Tannery Creek Systems. Tannery software development manager Jeff Bethune said in a telephone interview that his company's technology uses vehicle recognition rather than license reading.

Bethune said the system is effective at speeds up to 25 to 30 mph. It stores the profiles of cars it sees and recognizes those still there on the next go-round.

Such technology -- especially license plate readers -- has come into extensive use by law enforcement agencies around the world in the past decade or so, industry officials say.

It has a number of applications. Howland said the District has been using license plate readers to catch scofflaws for the past 2 1/2 years, increasing plates read fivefold.

In November, Chicago deployed a fleet of 26 similarly equipped boot vans, a spokesman said, each capable of checking 900 plates an hour.

Police departments in many cities, including the District, use the technology to hunt for cars that have been reported stolen. A North Carolina firm says its system can be used on interstate highways, where it can scan up to four lanes of moving traffic and check license plates against a "hot" list.

But such devices worry the American Civil Liberties Union.

"The question is: What are they being used for?" said Barry Steinhardt, director of the ACLU's Technology and Liberty Program in Washington.

Use of such technology for parking enforcement has "limited civil liberties consequences," he said. Using it to track people is a different matter.

"Are these going to become part of a system of 24-7 surveillance of individuals? Certainly, they can be used and have been used to track people who have other than motor vehicle violations," he said Friday.

"The thing that we fear -- that I fear -- the most is the use of license plate reading technology as part of a broader system of tracking or surveillance and movement," he said. "There's no real limitation in what it can be used for."

Michael Kelly, a product manager at Genetec, a Canadian firm that makes a plate-reading system the District is testing, said he has heard that criticism before.

"We heard it a lot before 9/11," he said. But afterward, "it disappeared pretty quickly."