Who's Too Old to Drive?

It seems to happen whenever there's a serious car accident involving an older driver: Legislators and the public clamor for more stringent license regulations for senior motorists. Since July, the chorus demanding reform has amplified, after a spectacular accident in which an 86-year-old California man lost control of his auto and crashed into a farmers market, killing 10 and injuring many others.

Currently, 22 states have tightened license-renewal requirements for older drivers. Wisconsin is not among them - so far. But Wisconsin Rep. Sheldon Wasserman (D-Milwaukee) recently said he planned to introduce legislation requiring more frequent testing of older drivers. Currently, all Wisconsin drivers with regular licenses renew them every eight years.

Do such laws lead to safer driving by seniors? Not necessarily, contends Edmund H. Duthie Jr., MD, Professor of Medicine and Chief of Geriatrics and Gerontology at the Medical College of Wisconsin, and his viewpoint is shared by the American Medical Association (AMA) and the influential advocacy group the American Association of Retired Persons (AARP). Why?

"It goes to a classic teaching of gerontology," Dr. Duthie says. "Biology and chronology are not necessarily predictors of one another, and safe driving is more a matter of functional ability than age" - although, he adds, "some functional ability is clearly age-related."

Those functions can include reduced vision, caused by diseases such as cataracts, macular degeneration (the leading cause of blindness in older people) and diabetic retinopathy. Other limiting conditions that increase with age are hearing loss, decline of cognitive ability (such as dementia), physical impairments like arthritis and the risk of sudden cardiac death.

On balance, though, Dr. Duthie says, "the debate over whether special licensing regulations for older drivers would improve traffic safety doesn't have a scientific answer - and it does raise critical issues about age entitlement and age bias." He cited an article reprinted in the Oct. 13, 2003, issue of the journal Archives of Internal Medicine, which said: "Efforts to predict crash risk based on advanced age, medical problems or medication profiles have been largely unsuccessful."

"Research is still needed," Dr. Duthie says, noting that the Medical College is among US medical institutions currently conducting epidemiological studies looking at the link between function and age.

As a clinician, Dr. Duthie says he is sometimes asked by older patients or concerned members of their families whether he thinks the older person can continue to drive safely. And not infrequently, he adds, the opposite happens - adult children ask him to reassure their parents that they can safely continue to drive. "Families suddenly find themselves on call to transport their parents everywhere, and they're angry and shocked by these new demands they suddenly face," he says.

Letting a Third Party Decide
Often - when there is doubt about the best course of action - Dr. Duthie arranges for an occupational therapist to see his patient. This therapist can administer a driver readiness test that simulates actual driving. (Such tests may be covered under Medicare, but Dr. Duthie suggests patients check ahead of time to make sure the costs will be reimbursed.)

If there's a particular medical question, he often defers to other specialists. "For instance," he says, "if a patient with a heart arrhythmia or diabetes is well-controlled, those conditions by themselves should not preclude driving. For more complicated cases, a cardiologist's or endocrinologist's opinion may be needed." Half of all vision problems in older drivers may be caused by cataracts. Once cataract surgery is performed by an ophthalmologist, the vision can be restored to a level that permits safe driving.

AARP opposes more stringent testing of seniors. Cheryl Matheis, AARP's director of state affairs, has said: "Age-based road testing is not a good solution. It's undeniable that people's abilities decline with age, but they decline differently at different ages." AARP takes the position that drivers of all ages should be tested more frequently throughout their driving lives.

"In a perfect world," Dr. Duthie says, "I would agree. But the financial resources may not be there" - especially now, when most state budgets, including Wisconsin's, are running deficits and must be brought into balance.

Older Drivers Often More Cautious
On the plus side, older drivers typically don't speed, tailgate (follow too closely) or drive drunk. And they tend to wear seat belts more than drivers in other age groups, according to NHTSA.

On the other hand, older drivers can have slower reaction time, tend to make more errors in concentration and comprehension, are more confused when traffic is congested, and may misunderstand signs. The most common driving errors older drivers make, NHTSA says, are failure to yield the right of way, making too-wide left turns and colliding with cars when backing up.

Many older adults, aware of their deficits, voluntarily begin to reduce their driving or stop driving altogether because they feel unsafe on the road or they lose their confidence, the AMA physicians' guide notes. They often avoid driving at night and during bad weather. The AARP Bulletin reported in August that two-thirds of people 50 and older had imposed limits on their own driving. It cited a study by the Massachusetts Institute of Technology and the Hartford Financial Service Group that found that older drivers as a group were not a safety hazard to others.

In its Before You Drive Checklist, the US Department of Transportation offers the following advice to drivers:

• Keep adequate space between you and the car in front: 1 car length for each 10 miles per hour.
• Make sure your mirrors and headlights are clean.
• Don't wear glasses with side pieces that can block your view.
• Don't drive too slowly - it is unsafe. Drive in the right (slower) lane when possible.
• Use familiar roads.
• Know signs by their shape and understand the standard traffic symbols
• Don't drive during rush hour.
• Don't turn or pass until you know you can do it safely. Always use your turn signal, and make sure it's off after you complete your move.
• Ask your doctor or pharmacist if any of your prescription or non-prescription drugs might affect your driving.
• If night driving becomes too difficult, don't drive at night.

The Costs of More Frequent Testing
An Oct. 19 Milwaukee Journal Sentinel editorial supported the legislation proposed by State Rep. Wasserman, while acknowledging the costs of implementing it. The Wasserman bill would require drivers between 75 and 94 to renew their licenses every two years; the licenses of drivers 95 and older would expire annually. Under the bill, older drivers would have to take a written test; and if they had committed a moving violation they would have to take a road test as well.

The editorial noted that the state several years ago lengthened the renewal period to the current eight years to save money. It acknowledged that retesting the state's 300,000 Wisconsin drivers between 75 and 95 years old would require hiring more state employees at a time when the state is trying to reduce its payroll. The Journal Sentinel applauded Wasserman's proposal, saying it would promote greater safety for older drivers, their passengers and other motorists. It endorsed the bill's proposal for financing the increased testing by requiring all drivers to pay $15 for each road test, and by increasing the renewal fees for drivers 75 and older by $2 annually.

Recently, the AMA, in association with the National Highway Safety Administration (NHTSA), released a "Physician's Guide to Assessing and Counseling Older Drivers," designed to help primary care doctors and other clinicians better assess which older patients may be medically impaired and thus need driver rehabilitation or counseling. Creating awareness of driver safety has been a continuing AMA priority since 1925, when the organization wrote its first of many policies about the potential medical risks of elderly drivers.

The newest AMA guidelines, however, emphasize Dr. Duthie's point that safe driving is a matter of functional ability, and not necessarily age.

What the Numbers Reveal
The worst drivers, measured by fatality rates compiled by NHTSA and published in the new AMA physician's guide, are 16-year-old boys. By age 17, those rates plummet, but from 17 through 24, male and female drivers continue to have significantly higher fatality rates than other drivers. From age 25 through 65, rates remain fairly low and constant. In general, younger drivers have high accident and fatality rates due to inexperience and drinking or other risky behaviors behind the wheel.

Although some drivers in their 80s and even 90s continue to drive safely, the odds in that age group are not good, according to NHTSA statistics. For drivers 65 and older, the crash rate per mile driven begins to increase slowly. For drivers 85 and over, NHTSA statistics show that the fatality rate per 100 million vehicle miles traveled begins to zoom upward to a rate 9 times as high as the rate for drivers between from age 25 through 69. As with the 16-year-olds, men 85 and older have worse rates than women.

In Wisconsin, the Associated Press recently reviewed state accident data from 1998 to 2002. It showed that drivers 81 and older had a higher accident rate per estimated miles driven than any other age group except the youngest drivers. It also showed that drivers 81 and older were in a reported accident twice as often as drivers 31 through 70. (A study of crashes involving older drivers in Wisconsin cited in the AMA guidelines found that drivers in the 65-to-74 age group did not pose a greater risk of serious injury or death for others than did younger drivers.)

Rather than just increasing testing of older drivers, Dr. Duthie says, "perhaps it would be more productive to retest those in the highest risk groups - very young as well as very old drivers. "Maybe we should go where the peaks are."

Physicians can influence their patients' decision to modify or retire from driving, the AMA physicians' guide notes. "Clearly," it says, "some older drivers require outside assessment and intervention when it comes to driving safety."

That is often a wrenching decision, Dr. Duthie says, because older drivers - like younger ones - like the independence of being able to go somewhere without waiting to be picked up. It's especially disturbing in areas that lack good alternate transportation.

One fact is certain, says Dr. Duthie. The number of older drivers will increase dramatically as the Baby Boom generation matures. Today, approximately 23 million drivers are 65 and older. By 2020, that number will nearly double, to more than 40 million. "If you think it's an issue now, just wait," he says.

Barbara Abel
HealthLink Contributing Writer

The US Department of Transportation website offers a thorough self-assessment called How Is Your Driving Health? A Self-Awareness Checklist & Tips to Help You Drive Safely Longer.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.