* Total -- 34,965
* Age 16-34 -- 15, 235, or 43 percent of total
* Age 60-85+ -- 6,812, or 19 percent of total
* Figures from 2010
Source: Insurance Institute for Highway Safety
Last week, 69-year-old Glenda Pinckard drove to five Chattanooga doctor's appointments, choir practice and church.
Driving takes extra concentration these days, she admits, but she's not ready to give up her keys.
"I'm still driving because the bus doesn't go where I need to go," she said. "I don't know how I would get where I need to go without driving."
There are nearly 34 million drivers 65 or older on the nation's roads, according to The Associated Press, and many face an uphill battle to stay safe behind the wheel.
"As we get older, our senses are not as good as they once were," Tennessee Highway Patrol Lt. John Harmon said. "In general, the older you are, things don't work as well as they used to."
Older drivers may have trouble hearing, seeing and reacting as quickly as younger drivers, he said.
As the number of older drivers climbs -- federal estimates show 57 million will be on the roads by 2030 -- many states have set up older-driver licensing requirements.
Some states ask older drivers to take eye exams, others require seniors to renew their licenses more frequently than younger drivers.
The stipulations vary widely between states, the AP reported. Tennessee does not have any older-driver requirements, but Georgia drivers who are at least 59 are issued licenses every five years instead of eight, and drivers 64 or older must pass a vision exam when they renew their licenses.
Iowa drivers must renew their licenses every two years after turning 70, while New Mexico drivers renew annually after 75.
Nationally, the crash rate of older drivers begins to climb as drivers hit their 70s and jumps sharply after 80, according to the Insurance Institute for Highway Safety.
In Hamilton County, the 2011 crash rate for drivers 65 and older is slightly higher than the rate for all drivers, according to the Tennessee Highway Patrol. The county's overall crash rate was 44.5 per 1,000 drivers, while older drivers maintained a 45.6 crash rate.
And young drivers -- age 15 to 24 -- are three times more likely to get in a wreck than older drivers in the county.
"The older drivers have their issues, but the younger drivers have more issues," Harmon said. "Their reflexes are good, but distractions are greater. They're texting and on the phone and multitasking in the vehicle."
Thirty-nine states have banned texting while driving, the Insurance Institute for Highway Safety reports. And while 30 states have some sort of older-driver licensing requirements, the laws tend to be hotly debated.
"Birthdays don't kill -- health conditions do," Joseph Coughlin, head of the Massachusetts Institutes of Technology's AgeLab, told the AP.
Opponents of older-driver licensing requirements argue that the requirements constitute age discrimination. New Hampshire repealed a law requiring road tests for 75-year-old drivers after an 86-year-old legislator called it discriminatory last year.
Still, most recognize the need for some sort of guidelines to ensure safety for older drivers. The National Highway Traffic Safety Administration suggests that every state create a program to improve older driver safety that includes renewing driver's licenses in person after a certain age.
East Brainerd resident Deborah Marks is celebrating her 61st birthday this week, and she said she doesn't drive as much as she used to.
"I find my reactions aren't as quick as when I was younger," she said. "Driving isn't harder, it's just more work, mentally. It's easier to take the bus."
About 60 percent of seniors voluntarily cut back on driving, said David Eby of the University of Michigan's Center for Advancing Safe Transportation throughout the Lifespan.
But the decision to stop driving is a tough choice, said Steve Witt, director at the Southeast Tennessee Area Agency on Aging and Disability.
"When someone can no longer drive, they have effectively lost their independence," he said. "I think people continue to drive as long as they can to maintain their independence."
Wayne Owens is the Hamilton County transportation director at the Southeast Tennessee Human Resource Agency, and his company provides contract transportation to local social service agencies. His buses make about 100,000 trips a year in the county and about 60 percent of those trips serve seniors or disabled people, he said.
"Generally speaking, our passengers don't have cars of their own or can't drive for one reason or another, so we are their last resort," he said.
Often, he added, family members worry about the safety of older drivers. In fact, the concern is so common that the company is considering investing $75,000 in a driving simulator. Drivers could use the simulator to judge their driving abilities without jeopardizing their safety.
"We're just beginning to look at possibilities," he said. "First, it could let them know intuitively whether or not they feel like they would be safe out in traffic. And second, it could give confidence to family members about the elderly person: 'Maybe I don't need to worry as much.'"
Older drivers who want to stay sharp can also enroll in a variety of driver safety courses. Chattanooga resident Pat Bailey has been teaching AARP driver safety classes for the past three years.
"We look at driving strategies, being prepared, knowing what to do ahead of time, always being aware of what's going on around you and knowing when it's time to hang up your keys," she said.
She uses videos, workbooks, homemade props and jokes to teach the eight-hour class, which many drivers take in order to receive a discount on insurance.
The most common traffic violation committed by older drivers is failure to observe the right of way, she said. Often, older drivers struggle to safely make left turns across traffic.
"Vision is probably one of the hardest things," she said. "They can't judge cars coming toward them, and peripheral vision is not as good to see if someone is on the side of them. That's why left turns are such a big thing."
She encourages seniors to keep their windows and mirrors clean, wear glasses that reduce glare and take the extra moment to turn and look when making turns.
But eventually, most drivers will need to hang up their keys, and Harmon said seniors should prepare early for that moment.
"We encourage seniors to think ahead and plan for when you'll have to give up your keys in a few years," he said. "Maybe your grandkids or your kids can take you to the store more often."
He also urged younger drivers to be patient as they take to the streets.
"Elderly drivers, young drivers, middle-age drivers -- we all use the roadway," he said, "and we all need to share it safely."
The Associated Press contributed to this report.