The signs sprang up in front yards almost as soon as news got out that the Bloomington nursing home and assisted living center known as Martin Luther Campus wanted to expand.

"STOP Martin Luther Manor expansion. Keep our neighborhood safe and quiet!" the maroon-and-white signs said.

It's a familiar story in Bloomington, where neighborhood opposition to new senior developments has become almost routine. At least four other recent developments aimed at seniors prompted vocal neighborhood opposition. People who live in quiet residential areas don't want new development that they see as too big, too tall and too busy.

Yet population forecasts show a silver wave washing over Bloomington. The same residents who spurred school construction in the 1960s are nearing retirement.

Bloomington already has more residents age 60 and older than it has under age 20, and many of those seniors want to stay in the city, even if they don't want to stay in single-family homes.

At least half of the residents of new senior developments are from Bloomington, and another quarter are the parents of city residents, said Larry Lee, director of community development.

"People have social networks here, churches and friends, and they don't like to move away," he said.

Bloomington has 1,251 condo, apartment and other independent senior-living units and 132 assisted-living apartment units. Another 588 independent units and 39 assisted-living units have city approval. The city has more than 21,400 single-family homes and about 3,600 townhouses.

Victor Johnson, an attorney who is a leader of the campaign against a Martin Luther expansion, questions whether the city really needs more senior housing.

"I'm 72, and I'm still living in my home and I hope to stay in it for a while," he said. "If you look at all the city's planning stuff, it all discusses senior residents. It appears to be a good way to get whatever you want built."

Martin Luther has not yet submitted an official plan to the city. On its website, it says it has permission from the state to "reconfigure" the existing nursing home, keeping the same number of beds. If the city approves a new building, "traffic and parking levels will stay the same" and the nearby Minnesota River bluff will be protected, the website says. It also says Martin Luther is considering a later phase that could include a "catered living facility," a sort of apartment building with resident services.

Johnson said more than 120 residents have signed a petition against any expansion. He said he and his neighbors, who live on the city's east side in a quiet residential area near the river that's accessed by just two main roads, do not oppose rebuilding the nursing home. But they worry about new traffic from an apartment building.

Speeding vehicles and noise created by ambulances and trucks already is a concern, Johnson said. There are few sidewalks in the neighborhood, and a school and a playground is nearby.

The need for senior housing in Bloomington is real, said Bob Hawbaker, the city's planning manager. He believes the supply is "not yet adequate."

"There comes a time when many [seniors] just don't want to worry about taking care of properties, or want the freedom to leave for the winter without worrying about a house, or want the security of having others around to check on them," he said in an e-mail. "There will be a lot more people in this situation than there are units now available to accommodate them."

Lee said he doesn't think residents' repeated opposition to senior developments is anti-senior. What people usually oppose, he said, is density -- multi-story developments that have many people living in a relatively small space, as they do in senior condos and apartments.

"But the future of communities like Bloomington is in adding residential density," Lee said.

Steve Peterson, the City Council member who represents the ward where Martin Luther is, said people just don't want neighborhoods they love to change.

"People are more accepting of change in an area where they see a problem," he said.

Peterson remembers when all the development in Bloomington seemed kid-centered -- schools, single-family homes, parks. Now, he said, Bloomington is seeing the flip side of that trend, and the city needs to plan for a future that looks increasingly gray.

"We don't want people to have to move to other cities, and we don't want people to have to stay in their houses if they don't want to," he said.

On Wednesday, a forum on vital aging and communities will be held in Bloomington by the Vital Aging Network, a group of older people who promote involvement of senior citizens in community affairs. One supporter of that group is the Metropolitan Area Agency on Aging, led by executive director Dawn Simonson.

"These are very big questions for communities to answer," Simonson said. "The answer is to be thoughtful now about what we're building for the future, and what will promote a high quality of life for all ages."

That can mean something as simple as a discussion about sidewalks, which many suburbs lack but offer a safer place than the street for children on bikes and for people who use walkers or wheelchairs.

Peterson said he doesn't want Bloomington to become a Minnesota version of Sun City, Ariz., where businesses focus on providing dentures and hearing aids. But, he said, it should be "a place where seniors want to be."

"We want good housing for families, for young people, for people who are active and without kids, and beyond that," he said. "It's about striking a balance for everyone."

Mary Jane Smetanka • 612-673-7380