Almost half the nation's older drivers worry about losing their freedom and mobility when it's time to give up driving, according to a new survey by auto club AAA.

Eighty-eight percent of drivers 65 and older said the inability to drive would be a problem, and 57% said it would be a somewhat serious or very serious problem.

"By 2020 — just eight years from now — it's estimated that nearly one in six people will be age 65 or older," says Robert Darbelnet, president and CEO of AAA. "No matter how active and healthy seniors are today, it's evident that giving up the keys is still a top concern."

Perhaps helping to dispel the notion that older drivers are more dangerous, AAA found that drivers 65 and older often "self-police": 61% don't drive in bad weather, 50% avoid night driving and 42% don't drive in heavy traffic.

The national telephone survey of 2,017 adults, including 512 aged 65 and older, was conducted in December for AAA. It has a margin of error of /-4.9 percentage points.

As 10,000 Americans turn 65 every day, the findings show a high level of concern among one of the fastest-growing groups of drivers on the roads. Anxiety about losing their mobility is justfied, says Amy Levner, AARP's manager of home and family issues. "On any given day, half the people who no longer drive are stranded at home," she says. "For most people, when they stop driving, they simply slide over and become a passenger."

Levner says most seniors who give up the keys either have no access to public transportation or are reluctant to use it. The anxiety reflected in the AAA survey reflects the reality of a society built around the automobile, she says.

Communities used to be designed around individual pedestrians, and roads were meant to be shared by all users — before the era of suburbanization, Levner says. "Now, folks are graying, and growing older, and getting stranded in the suburbs," she says.

AARP recommends that families with a senior who quits driving set up a regular schedule of rides with family and friends for activities such as doctor's visits and shopping trips.

Catherine Sinclair-Williams, 77, of Elmont, N.Y., says she's been a licensed driver for 6o years and expects to keep driving for at least an additional 16. "My dad drove until he was 92," says Sinclair-Williams, who's retired after careers at a telephone company and as a third-grade teacher. "I think maybe I can outlast him."

Sinclair-Williams, who drives about 200 miles per week, says she has cut back on driving at night since being diagnosed with glaucoma. She says she hasn't had a citation in more than 10 years and drives as well now as she did at 30. "I'm an old young woman," she says. "I go into Manhattan every other week."

She says losing her car would be devastating. "My car is very, very important," she says. "I must have a car."

© 2012 USA TODAY, a division of Gannett Co. Inc.