EDITOR'S NOTE: The Associated Press and the Associated Press Managing Editors have launched a joint project to look at the silver tsunami - the aging of the baby boomers - and its impact on communities and the services they provide, from health care to accessible housing and shopping. This story is the first in a series.

NEW YORK - America's cities are beginning to grapple with a fact of life: People are getting old, fast, and they're doing it in communities designed for the sprightly.

To envision how this silver tsunami will challenge a youth-oriented society, just consider that seniors soon will outnumber schoolchildren in hip, fast-paced New York City.

It will take some creative steps to make New York and other cities age-friendly enough to help the coming crush of older adults stay active and independent in their own homes.

"It's about changing the way we think about the way we're growing old in our community," said New York Deputy Mayor Linda Gibbs. "The phrase 'end of life' does not apply anymore."

With initiatives such as using otherwise idle school buses to take seniors grocery shopping, the World Health Organization recognizes New York as a leader in this movement.

But it's not alone.

Atlanta is creating what it calls "lifelong communities."

Philadelphia is testing whether living in a truly walkable community really makes older adults healthier. In Portland, Ore., there's a push to fit senior concerns such as accessible housing into the city's new planning and zoning policies.

Such work is getting a late start considering how long demographers have warned that the population is about to get a lot grayer.

"It's shocking how far behind we are, especially when you think about this fact - that if you make something age-friendly, that means it is going to be friendly for people of all ages, not just older adults," said Margaret Neal of Portland State University's Institute on Aging.

While this fledgling movement is being driven by nonprofit and government programs, New York aims to get private businesses to ante up, too.

Last year, East Harlem became the city's first "aging improvement district." Sixty stores, identified with window signs, agreed to put out folding chairs to let older customers rest as they do their errands. The stores also try to keep aisles free of tripping hazards and use larger type so signs are easier to read. A community pool set aside senior-only hours so older swimmers could get in their laps without faster kids and teens in the way.

On one long block, accountant Henry Calderon welcomes older passers-by to rest in his air-conditioned lobby even if they're not customers. They might be, one day.

"It's good for business but it's good for society," too, he said.

The size of the aging boom is staggering. Every day for the next few decades, thousands of baby boomers will turn 65. That's in addition to the oldest-old, the 85- to 90-somethings whose numbers have grown by nearly one-third in the past decade, with no signs of slowing.

By 2050, 1 in 5 Americans will be seniors. Worldwide, almost 2 billion people will be 60 or older, 400 million of them over 80.

That's almost always viewed as a health issue, preparing for the coming wave of Alzheimer's, or as a political liability, meaning how soon will Social Security go bust?

"We think this is something we should be celebrating," says Dr. John Beard, who oversees the World Health Organization's Global Network of Age-Friendly Cities. "They need to live in an environment that allows them to participate."

In East Harlem, a yellow school bus pulls up to a curb and 69-year-old Jenny Rodriguez climbs off. The bus had already dropped a load of kids at school. Now, before the afternoon trip home, it is shuttling older adults to a market where they flock to fresh fruits and vegetables.

Rodriguez usually goes shopping on foot, pulling along a small cart. It can be a hike. Supermarkets aren't too common in this lower-income part of the city, and there's less to choose at tiny, pricier corner bodegas.

"You can only buy so much. Some streets, the cracks are so bad, you're pushing the shopping cart and almost go flying," Rodriguez said, examining sweet potatoes that she pronounced fresher and cheaper than at her usual store. "This is so much easier."

More than 200 times, school buses have taken older adults from senior centers to supermarkets in different neighborhoods. It's just one of a variety of initiatives begun in 2009 by the New York Academy of Medicine and the city's government to address the needs of older residents. Already, they're showing results.

A city report found the number of crashes has dropped at busy intersections in senior-heavy communities where traffic signals now allow pedestrians a few more seconds to cross the street.

Benches have been placed in nearly 2,700 bus shelters to give waiting seniors a place to rest.

The city's aging taxi fleet is scheduled to be replaced by a boxier model designed to be easier for older riders and people with disabilities to open the doors and slide in and out.

On the Upper West Side, seniors snapped up a report card of grocery stores deemed age-friendly because they offer deliveries, have public bathrooms - a rarity in the city - and sell single portions of fresh meat, poultry or fish, important for people who live alone.

Artists volunteer to teach at senior centers in return for space to work on or display their own creations.

And a "Time Bank" is letting hundreds of people of different ages and with different skills essentially barter services. A retired English teacher may do some tutoring, for example, and use the credit she earns to get computer help from another volunteer.

Aging expert Andrew Scharlach of the University of California, Berkeley, sees a common thread in these changes and the work of other cities. Combat the social isolation that too easily sneaks up on older adults and it has a huge impact not just on how many years they will live, but how well they live them.

Cities and suburbs were designed for younger people, full of stairs and cars, he explained. As they become increasingly difficult to navigate, older people gradually retreat.

Revamping a lot of infrastructure may not happen in a tough economy. But some communities are building age-friendly changes into planned upgrades or maintenance, such as New York's street crossings, or into requirements for future development.

The WHO's Beard says some changes aren't that costly, noting that seniors around the world say more benches and access to bathrooms will help them get out and about.

Among other cities' work:

n The Atlanta Regional Commission's Lifelong Communities Initiative is pushing communities that help people age in place. Efforts are under way in six metro areas, including work to adapt zoning codes to allow more of a walkable mix of housing and retail. The Mableton community of suburban Cobb County is planning that kind of a town square, and has opened a farmers market - on a weekday morning when seniors preferred to shop - and intergenerational community garden. To the east, DeKalb County is building a library near a senior center, planned senior housing and a bus stop. One town pilot-tested a shuttle for seniors to supplement bare-bones public transit.

The Atlanta Housing Authority is working with the commission to retrofit high-rise apartments that house a lot of older residents, with the goal to improve access to the surrounding community. At one site under construction, changes include a ramp entrance, safer sidewalk to the bus stop and more time for pedestrians to cross the street.

The overall move isn't without controversy.

Sometimes younger residents misunderstand and say they don't want to live in a retirement community, said commission urban planner Laura Keyes.

She said boomers, who are classified as being born from 1946 to 1964, and millenials, the children of baby boomers who came of age in the new millennium, ultimately want the same things: access to shopping, green space, more freedom from the car. The idea is a mix of ages but where older residents don't need to move if their health fails.

Keyes became interested in age-friendly communities when visiting friends in nursing homes built in commercial districts - and saw that they had nowhere to take a walk.

n Philadelphia is the oldest of the nation's 10 largest cities, with 19 percent of its residents over age 60 - and lots of multi-story rowhouses where seniors are stuck on one floor. "They become prisoners in their homes," said Kate Clark of the nonprofit Philadelphia Corporation for Aging.

In redesigning the city's zoning code, proposals are being debated that would allow seniors to rent out their upper floors, and to require that a certain amount of new housing be what's called "visitable" - with such things as ramp entrances, wide hallways and at least a half-bathroom on the main floor, she said.

With funding from the National Institutes of Health, the aging group's Allen Glicksman is studying if seniors who live in a walkable neighborhood really are healthier as a result. He has found that social capital - think friendly neighbors, low crime and good sidewalks that encourage getting out - is as important to older residents as access to supermarkets, public transportation and good housing.

Also, there are calls for age-friendlier parks, with safer steps and places to walk apart from bikers.

To sustain momentum, Clark created GenPhilly, a network of 20- and 30-somethings interested in shaping the city they'll age in by raising senior issues in varying professions.

n Portland was part of WHO's initial study of what makes a city age-friendly, an initiative that helped bring about more handicapped-accessible cars for the city's light-rail system, Neal said.

Now, aging experts are among the advisers as the city develops a master plan for the next 25 years. One issue, Neal said, is how to develop more accessible housing when the city's anti-sprawl policy means a lot of narrow, multistory houses are being squeezed into empty city lots - near transportation but still not age-friendly with all the stairs.

Integrating senior-friendly changes into everyday city policies is less visible than, say, a new retirement home but it's ultimately the goal, says Scharlach, the aging expert.

New York also hopes for some economic return.

Consider La Marqueta in East Harlem. Fifty years ago, it was a bustling, five-block market, a weekly gathering spot for families. But economic downturn left the city-owned building mostly empty for years. Now, as part of a $1.5 million economic revitalization project, an industrial kitchen in the building will train low-income women to start their own food businesses. It joins the fish and butcher shop, a farmer's market, and a high-end food importer - and busing in the seniors once a month boosts the still thin customer traffic.