TAMPA - Anticipating the day they would quit driving wasn't the main reason Mack and Susan Hicks left the suburbs for a new condominium in downtown St. Petersburg. Now that they've settled into the city, however, they are enjoying a life with fewer car trips.

"Now my husband jokes that if his dentist isn't within walking distance, he isn't going to the dentist," Susan Hicks said.

Retirees such as the Hickses are part of a migration of the aging into cities that is expected to accelerate as the baby-boom generation reaches retirement age.

For many in the post-World War II generation, the oldest of whom are now turning 60 at the rate of 10,000 a day, life in the suburbs after the kids move out seems like a life isolated from society, especially as they contemplate the day when they are too old to climb behind the wheel after dark, or can't drive at all.

"That dream house in the suburbs?" said Joseph Coughlin, founder of the Age Lab at the Massachusetts Institute of Technology. "The inability to drive may maroon people there."

In response, the oldest of the boomers are starting to repopulate downtowns in medium-sized and larger cities where doctors, restaurants and shopping are a short walk or a bus ride away.

St. Petersburg's and Sarasota's downtowns are booming with new condominiums, many of them equipped with amenities to attract retirees and boomers making that final commute - back into the city. Tampa appears headed in the same direction.

Changes To Come

Like everything else they've touched in their lifetimes, the boomer generation can be expected to transform those downtowns and public transportation. Among the changes:

•With more seniors living in urban cores, there may be fewer older drivers on the road.

•Vehicle designs will adapt to aging boomers who stay behind the wheel.

•Buses and other public transportation modes will adapt to the elderly.

•New "urban village" designs will place more services and amenities within walking distance.

Matt Thornhill, whose Richmond, Va., consulting firm, The Boomer Project, studies the nation's 78 million boomers, said they have been making big imprints on our culture since birth.

"Look," Thornhill said, "when we were babies, there were so many of us that Gerber put strained peas in a jar and became a billion-dollar company almost overnight."

Then came Saturday morning cartoons, he said, and Kellogg invented cereals especially for kids. Then all those teens needed burgers and fries right now, and McDonald's stepped up; they got older and fatter, and Nike made millions off their exercise regimens; they became parents, and Detroit invented the minivan.

He expects many more innovations to accompany boomers into retirement. Those who move into cities and wean themselves from the automobile will find changes in public transportation. Those who remain behind the wheel will find changes in automobile designs to suit their slowed reflexes.

Persuading boomers to give up their cars entirely will be a challenge.

"They'll never give them up, at least that's what they think," said St. Petersburg Realtor Cary Bond Thomas, who sells downtown condominiums. "Even when older couples come in and want to buy a $1.3 million condo downtown, these days the first thing they ask about is the two [or three] reserved parking places."

Activity Driven

For boomers, the car has been integral to their lives, Coughlin said. It has been the key to their independence since they were teenagers.

"Heck, many of their children were conceived in a car," he said.

Since then, it has ensured their ability to get to and from the activities that make up their lives, that keep them connected socially and will, for many, enable them to continue working past the traditional retirement age, if they choose.

But as older drivers make up an increasingly large percentage of those behind the wheel, the danger for everyone grows proportionately. Drivers older than 75 have the second highest fatality rate on the nation's roads; only drivers of ages 16 to 24 cause more deadly wrecks.

With boomers expected to live longer than any previous generation, there is an added incentive to having urban cores where cars are not an integral part of their lives.

If lifelong transportation is the goal, the car - that symbol of freedom since high school - likely will not be the means to achieve it, Coughlin said.

Although life expectancies have risen from 47 years old in 1900 to 77 years old in 2000, aging still takes its toll on physical strength and flexibility, mental agility and for many, susceptibility to injury and illness, Coughlin said.

As that happens, "the very things we cherished when younger, our homes and our cars, may now threaten our independence as older adults," Coughlin said.

"We've spent billions to achieve longevity, but we've made few investments in the infrastructure necessary to ensure healthy, independent living in our later years."

In 1900, 1 in 8 adults was older than 65; by 2040 it will be 1 in 5.

Public Transit Must Evolve

Coughlin said that one goal of the Age Lab is determining how to leverage existing information and vehicle technologies to provide responsive public transportation systems that provide door-to-door services for those who choose to remain in their homes. Organizations to provide rides-on-demand to seniors are being created across the country.

Auto makers are already adapting "universal design" principals to make vehicles safer and more user-friendly for older drivers, including adjustable pedals, better mirrors, more effective lighting, louder horns, and more adjustable and supportive seats.

Federal and state highway departments have been incorporating improvements to intersection design, clearer signs, longer signal lights for drivers and pedestrians, and intersection lighting into current highway projects. "Intelligent Transportation Systems" are adjusting signal lights and using variable message highway signs to manage traffic.

Bus systems are evolving into true "bus rapid transit" in some areas, with bus stations elevated so passengers can walk, not climb, onboard. New systems make better time by including specially designed signals to ensure that buses get green lights, or buses run in their own corridors or in special commuter lanes.

Advanced mass transit will serve aging boomers well, Thornhill said, but researchers are finding that if public transportation is not convenient, comfortable, responsive - and a generally pleasant experience - it won't be used by boomers.

Where there aren't improvements, those older drivers will remain on the road.

Home Telecommuting

One promising partial solution may be a version of telecommuting to obtain certain services, enabling seniors to measure their own vital signs so physicians can conduct routine evaluations over the telephone or by computer, he said. Computer interfaces also can enable virtual, interactive attendance at governmental and other meetings, making some trips unnecessary.

"We need to throw every tool at our disposal at the problem," said Phil Winters of the University of South Florida's Center for Urban Transportation Research. "And that certainly includes technology."

Boomers are used to being the center of public policy and social change from struggles for civil rights, women's rights and ending the Vietnam War - not to mention the Hula-Hoop, Pet Rock and Lava Lamp - and by the sheer weight of their numbers, their influence should continue, Thornhill said.

If not, longevity, one of the great gifts of technology, could make boomers' retirements more like solitary confinement than those dreamed-of years of freedom and fulfillment after a working lifetime.