Monitors promise greater liberty, safety

GPS provides new alternative to jail

That's because GPS systems can suffer signal failures just like cell phones. When someone enters the Harbor Tunnel, for instance, communication with satellites is broken.

Several cities and counties have found less-sophisticated GPS systems - called "passive" systems - to be inadequate. In a passive system, an offender plugs the GPS unit into a holster at the end of the day, which triggers data transmission. Under this system, an offender's whereabouts aren't digitally tracked until that happens.

Tammy Brown, a spokeswoman for the Maryland Department of Juvenile Services, said that if the General Assembly approves $1 million for GPS tracking of at-risk children, the agency plans to use an active monitoring system.

The GPS trails would be checked round-the-clock from the Baltimore Police Department's watch center, where the city's street cameras are monitored.

"The idea of having it in the watchtower is that working with police, they'll be able to help us when kids go into an area where they're not supposed to be," Brown said. "They'll be able to quickly notify a patrol officer, who can help respond."

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