A $23 million proposal to place more than 3,000 cameras around public-housing developments has alarmed privacy advocates and raised questions over the effectiveness of surveillance systems.

Under the plan, the Chicago Housing Authority would install the cameras near 16,000 apartments in the city, about three quarters of the authority's properties, and it would update surveillance systems installed earlier at public housing for seniors. Officials say the program would improve safety and security around residents' homes.

Already, more than 2,000 cameras in the city link to an emergency command center, making Chicago's residents some of the most closely watched in the world. Mayor Richard M. Daley has said that if Chicago wins the 2016 Olympic bid, he would like a camera on every street corner of the city.

CHA officials recommended the proposal during committee meetings last week, but they must approve it during a board meeting tomorrow. Funding for the surveillance system would come from the American Recovery and Reinvestment Act, this year's federal stimulus package.

Authority spokesman Matt Aguilar says the proposal is a response to residents' calls for more cameras over at least the last two years.

"We continually get phone calls about this," Aguilar says. "It's a consistent concern."

Aguilar says that while officials meet regularly with the authority's local advisory councils, it was not until about a month ago that they discussed the camera plan with the Central Advisory Board, which represents residents across all CHA developments.

That was after the authority put out a request for proposals from potential contractors in April.

"There isn't really any sort of public dialogue, ever, about how much is enough or what's effective," says Ed Yohnka, spokesman for the American Civil Liberties Union of Illinois. "There's no real, definitive evidence that any of this is effective. There are just pronouncements that it is."

Yohnka and other civil-liberties advocates have acknowledged that people should not expect privacy in public places, but he questioned the extent of formal talks between officials and residents, and called the number of cameras in the authority's plan "extraordinary."

"You could literally have police staring into people's homes, and places of work, and into their cars," he says. "These systems are, sort of, fraught with that possibility given their power and their reach."

Existing cameras in Chicago can tilt, zoom and alert dispatchers of suspicious activity. To develop the surveillance system, city officials drew ideas from Las Vegas casinos, the Pentagon and London, considered the world's most minutely observed city.

It is not yet clear how 3,198 new cameras at the authority would operate, or where officials would place them. Officials selected Siemens Building Technologies Inc. as the proposed contractor after a competitive bid process in April.

Aguilar says that if the plan goes forward, the authority would consult with residents on the system's design.