Washington ? 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.

A staggering aging boom

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.”

Addressing needs

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.

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.

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.

Age-friendly changes

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.