In the most ambitious project, New York City police announced plans several years ago to link 3,000 public and private security cameras across Lower Manhattan designed to help deter, track and detect terrorists. The network is not yet complete.
How they affect crime is open to debate. In the largest U.S. study, researchers at UC Berkeley evaluated 71 cameras that San Francisco put in high-crime areas starting in 2005. Their final report, released in December, found "no evidence" of a drop in violent crime but "substantial declines" in property crime near the cameras.
Only a few communities have said no. In February, the city council in Cambridge, Mass., voted not to use eight cameras already purchased with federal funds for fear police would improperly spy on residents. Officials in nearby Brookline are considering switching off a dozen cameras for the same reason.
Lancaster is different, and not just because it sits amid the rolling hills and rich farms of Pennsylvania Dutch country.
Laid out in 1730, the whole town is 4 square miles around a central square. Amish families still sell quilts in the nation's oldest public market, and the Wal-Mart provides a hitching post to park a horse and buggy. Tourists flock to art galleries and Colonial-era churches near a glitzy new convention center.
But poverty is double the state's average, and public school records list more than 900 children as homeless. Police blame most of last year's 3,638 felony crimes, chiefly thefts, on gangs that use Lancaster as a way station to move cocaine, heroin and other illegal drugs along the Eastern Seaboard.
"It's not like we're making headlines as the worst crime-ridden city in the country," said Craig Stedman, the county's district attorney. "We have an average amount of crime for our size."
In 2001, a local crime commission concluded that cameras might make the city safer. Business owners, civic boosters and city officials formed the Lancaster Community Safety Coalition, and the nonprofit organization installed its first camera downtown in 2004.
Raising money from private donors and foundations, the coalition had set up 70 cameras by last year. And the crime rate rose.
Officials explained the increase by saying cameras caught lesser offenses, such as prostitution and drunkenness, that otherwise often escape prosecution. The cameras also helped police capture and convict a murderer, and solve several other violent crimes.
