The housing market's continuing struggles have upset the retirement plans of millions of Americans, keeping more of them in their current homes, waiting for diminished equity to reappear.

Others plan to move, but they appear to be demanding something much different from what they wanted before the real estate boom turned to bust: smaller, less expensive retirement houses they can afford with their reduced means.

At the start of the financial crisis in the fall of 2008, economists weren't anticipating that the long-term trend toward retirement living would be derailed. After all, the 2001 recession had only a short-term effect on this segment of the market nationwide, they said, and sales rebounded quickly.

This time, however, the economists were dead wrong. So wrong, in fact, that in the West, long a destination for retirees, for-sale housing built for seniors has been converted, for now, into rental apartments.

For aging baby boomers and others who have decided to stay put, or the millions of older Americans who were never planning or even able to move, there is growing concern that cutbacks in public and private programs have eroded available services.

AARP, the national group that lobbies for older Americans, is establishing pilot programs in several states and the District of Columbia this year to help create environments that help seniors "remain healthy, active, and engaged in their communities for as long as possible," said Grace Rustia, the organization's associate state director.

New York and Portland, Ore., are two of AARP's "age-friendly" cities. Among the programs being tested there are extending street-crossing times and setting up emergency-alert systems for missing elderly adults.

Philadelphia, too, is looking to become as "age-friendly" as possible, setting goals to make it one of the World Health Organization's network of communities that look out for the well-being of their older residents. Deputy managing director for aging Lydia Hernandez Velez said the city's Commission on Aging has developed a strategic plan to make that happen and expects to have the details completed by summer for implementation in the fall.

"The biggest piece of the effort," Velez said, "was the creation of my position," designed "to put a lens on" a significant demographic shift in the local population.

Rustia said AARP is working with the commission on the needs-assessment portion of the plan, which will help Philadelphia become a "livable community" for older people, with a primary focus on housing and transportation needs.

"The assessment stage involves looking at everything and putting together activities and funding for them to meet the challenge," Velez said.

They have their work cut out for them: The 2010 Census showed there were 312,000 people 54 years and older in Philadelphia, with those numbers projected to surge by 2015.

The current population looks at growing older differently than previous generations did because improved health care is extending life spans, experts say.

Not only does the city need to accommodate a growing and ever-more-diverse aging population, but it also will have to work on the persistent problems of the 19 percent of Philadelphia senior citizens who live in poverty.

One thing the city is looking at is "naturally occurring retirement communities" — areas of Philadelphia where large numbers of seniors are concentrated. The term describes Old City, Society Hill, and Queen Village, where almost four years ago a group of aging residents who wanted to remain in their houses founded Penn Village, a 501(c)(3) nonprofit corporation.

Penn Village was modeled on similar organizations in Boston and Washington, another AARP age-friendly community. In return for an annual membership fee, participants are entitled to basic services such as grocery shopping and rides to the hospital or doctor's office. There are social opportunities and ways to volunteer to help others.

The city's strategic plan will attempt to address many issues, including how neighborhoods can help elderly residents; providing easier access to transportation and programs designed to help the elderly; and promoting volunteer and employment opportunities for seniors.

The rowhouse, architecture of choice for hundreds of thousands of city dwellers, offers significant challenges to aging Philadelphians, Velez said, including accessibility.

"There are efforts to deal with these issues in new construction," especially in promoting "visitability," for example, making it possible for people in wheelchairs to engage in the life of the community through accessibility.

Another way to help rowhouse dwellers "age in place" is by changing zoning codes to permit creation of smaller but inclusive units within homes for live-in caregivers. In addition, many houses dating from the turn of the 20th century have second-floor bathrooms, and older homeowners could benefit from the opportunity to add bathrooms to the first floor so they don't have to climb up and down stairs.

"These are problems that cannot be solved overnight, but they need to be talked about," Velez said. "The opportunities are minuscule compared with challenges."

Contact Alan J. Heavens at 215-854-2472, or@alheavens at Twitter.