DRIVING ABILITY

Transportation is a critical link for independent living and healthy aging; and for many people in the United States, transportation is defined as driving. Whether it is a trip to the grocery store, to volunteer, to see a doctor, to visit a friend, or to simply experience the joy of getting out, the automobile is the means for most people to remain active and healthy contributors to society.

Moreover, there is often no viable alternative to driving. The majority of older adults in the United States live in suburban and rural locations where public transportation services are either modest or nonexistent. Other transportation services, often providedby faith-based organizations, community centers, or those that are part of a regional transportation system, typically provide only basic service to doctors and food stores.

Future generations of older adults are likely to place an even greater demand and reliance on driving. For the rapidly aging baby boom generation (those born between 1946 and 1964), life has been based on and built around the mobility of the automobile. Research suggests that the majority of the baby boomers will choose to age-in-place in the suburban and rural communities that make safe walking a challenge and where distances to stores and other activities can be many miles.

Moreover, as this group ages, they are likely to travel more than their parents and grandparents. Improvements in health, greater incomes, and higher education levels lead to a greater desire to get out and participate in an active lifestyle of part-time work, volunteering, social and entertainment activities, and recreation. Sarah Bush (2001) has suggested that the changing role of women may also place additional demands on the car. Women are likely to drive more in the future due to independent lifestyles developed at a younger age, including professional careers, greater income, and more education. Lifestyle factors, housing patterns, and socioeconomic factors suggest that the next wave of retirees will want to lead an active and mobile life—which, for now, only the automobile can support.

There are a number of safety concerns about the ability of older adults to continue to drive safely in their advanced years. Transportation statistics indicate that drivers between the ages of sixteen and twenty-four have the highest fatality rate, with drivers age seventy-five and older having the second highest rates. Those arguing that older drivers present a risk to themselves and others on the road cite these data as supporting their concern that older drivers are unsafe, or that they should be tested more often than younger drivers. The statistics are not as clear as their argument would suggest, however. Researchers are uncertain about why adults over seventy-five experience high fatality rates. Many argue that older people are more likely to die in a crash, not because they are the cause of such an accident, but because they are more fragile than younger drivers and are more likely to die from an injury. The ambiguity surrounding driving ability, who can drive safely, and what an older driver is presents a continuing personal and public policy dilemma—one that is made more complex by the importance of transportation to people's lives, the uncertainty of how age affects driving skills, the lack of accepted testing technology, and the absence of viable alternatives to the car.

The natural aging process and driving ability

Nowhere is the ambiguity surrounding the older-driver issue better demonstrated than in attempts to identify who is old. As people age, their physical, mental, and cognitive capacities begin to change. In addition, age-related diseases, and the medicines used to treat those conditions, may also affect capacity. Figure 1 illustrates some of the systematic changes that tend to affect people, to varying degrees, as they age. Within this context, the discussion of older-driver safety arises. Are older people mentally and physically capable to drive? In most cases, the answer is a resounding "yes."

Physical, perceptual, and cognitive function

Over time, one may expect to experience weaker (or somewhat diminished) physical, perceptual, and cognitive function. These changes, which can occur as early as age forty, include reduced capacity of vision at night and weaker contrast sensitivity, which makes signage along roadways more difficult to read. Most people also experience an increased sensitivity to glare during night driving, and many have difficulty recovering from bright lights. Hearing loss usually accompanies aging. Most people compensate for both visual and auditory changes as they happen, and do not realize that their abilities have declined over time.

Decreased strength and flexibility also typically accompany aging. While these may be offset with regular exercise and strength training, most people exercise less frequently as they age, when they should be exercising more to compensate for weakening muscle and bone mass. These problems lead to more problematic neck and trunk rotation, in addition to difficulty accessing a vehicle or turning the head to compensate for natural blind spots in the car to view oncoming traffic or pedestrians. For some, these physical changes may contribute both to a reduced desire to travel and more difficulty in concentrating on the entire situation of driving. The speed with which most people perform routine and simple tasks slows as they age because movement is more difficult as muscle strength and flexibility decrease.

Individual perceptions change over time as well. For example, some research indicates that capacity for judgment of velocity and distance of approaching vehicles becomes reduced with age. This judgment is a crucial component in the driving process, and when it is impaired it may cause an accident. The driver who cannot accurately determine the distance and speed of an oncoming vehicle risks an accident when making a left turn at an intersection.

People begin to react more slowly to stimuli as they age because response times begin to slow. While driving, a split-second decision can be the difference between an accident and a close call. Reaction time is an important feature of driving because a driver must see a problem, think about it, and then react—apply the brake, steer, or take another action as necessary. As shown in Figure 1, attention is made up of many linear subtasks that lead to action. The stimulus affects the sensory processes in the brain, which affect perception, information processing, and response, all of which are key components of attention. The longer it takes for each response, the longer it takes for the intended action. This leads to problems concentrating on the many subtasks that must be considered while driving. Synthesizing multiple pieces of information and conducting the many actions of driving may sometimes overwhelm the older driver who cannot react quickly to a stimulus.

Self-regulation

Age-related restrictions on the relicensing of older drivers in the United States is an issue that affects millions of people. While it affects the driver directly, it affects many people indirectly. Someone's ability to continue driving affects the people who may depend on that person for transportation; it affects that person's spouse, family and friends, who are concerned both for the person's happiness and quality of life, and it affects public safety officials, who must remain vigilant of potential problems.

Most older drivers are safe drivers. Although a popular public policy debate, regulating older drivers is done principally by the individual, not government, and with great success. In other words, older drivers routinely practice self-regulation—they choose not to drive in conditions that they believe are difficult or may present a dangerous situation. For example, most older drivers begin to drive less in the evening to compensate for diminished night vision and problems with glare. Other drivers feel less comfortable on busy highways, or driving in poor weather; choosing, therefore, routes and schedules that allow them to avoid troublesome conditions. Self-regulating driving behavior allows older adults to maintain their mobility and independence while optimizing their safety and the safety of others.

Government regulation of the older driver

Typically sparked by an accident involving an older driver, combined with the ensuing media coverage, the issue of what age is too old to drive has often become a debatable policy problem. While policymakers want drivers on the roadways to be safe drivers, they are not inclined to pass legislation limiting the driving of older adults. The issue is emotionally charged, as many older drivers in the United States have been driving for forty or more years and do not want to give up their privileges, and in most instances this is neither appropriate nor necessary. This fact, combined with uncertainty about defining old, deciding how best to assess driving skills, and a general lack of organizational capacity to implement such regulation, usually results in little if any regulatory change.

Ambiguity surrounds the definition of old. While some people in their fifties might have severe physical impairments caused by aging, others in their eighties might be perfectly capable of driving as safely as they were many years previous. Each state that regulates older drivers has determined the age at which the licensing laws change. The youngest age at which a state implements restrictions is fifty (in Oregon), while the oldest age at which point changes are mandated is seventy-five (in Illinois, Montana, New Hampshire, and New Mexico).

Typical relicensing restrictions on older drivers involve the length of time between renewals. In some states the duration of a valid license is reduced by some amount for older drivers. For example, Iowa allows drivers to possess a license for four years before renewal, but when a person reaches age seventy, his or her license is only valid for two years. These regulations provide the states more frequent control if drivers' abilities are slipping.

Another regulatory tool for older drivers is in the form of testing procedures. A few states that do not require periodic vision testing have implemented testing after a certain age, but most states require vision testing every few years for all drivers. A handful of states require a driving test at a certain age, and others require a driving test if the examiner at the Division of Motor Vehicles feels that the applicant should be tested. Tests for mental competency are not required by any state, but most allow the examiner the discretion of requiring further testing if necessary. Most states, however, at least suggest, if not mandate, that physicians must report individuals who are not competent to drive to the state licensing bureau.

One problem with testing older drivers is the lack of understanding surrounding the issue. No clear scientific study or policy consensus exists on the type of testing that would produce the most accurate results regarding the abilities of an older driver. Additional constraints include the budgets of licensing organizations, along with the question of what type of person would be the most qualified to give a test. While some people feel that anyone qualified should administer such a test, others question what makes a person qualified.

Summary

Many characteristics work together to contribute to a person's ability to drive safely. Physical capacity, mental acuity and competency, adequate reaction time, and appropriate skills are only a few of the abilities that must be considered when evaluating driving ability. Chronological age alone is not an appropriate predictor of how someone will function behind the wheel. Most older drivers are safe drivers, and they choose to drive when they are most capable. Moreover, the important role of driving to an older person's independence and quality of life makes the issue of driving ability, relicensing, and the search for viable alternatives to the car (when driving may no longer a choice) a critical and enduring challenge for an aging society.

Joseph Coughlin Meredith Coley

See also Aging in Place; Hearing; Memory; Reaction Time; Vision and Perception.

BIBLIOGRAPHY

Burkhardt, J. E.; Berger, A. M.; Creedon, M.; and McGavock, A. T. Mobility and Independence: Changes and Challenges for Older Drivers. Bethesda, Md.: Ecosometrics, 1998: 25–33.

Bush, S. "Does Future Elderly Transportation Demand Pose a Pending Crisis?" Public Policy and Aging Report 11, no. 4 (2001): 15–19.

Cobb, R. W., and Coughlin, J. F. "Are Elderly Drivers a Road Hazard?: Problem Definition and Political Impact." Journal of Aging Studies 12, no. 4 (1998): 411–427.

Coley, M., and Coughlin, J. F. "State Older Driver Re-Licensing: Conflict, Chaos and the Search for Policy Consensus." Elder's Advisor: Journal of Elder Law 3, no. 4 (spring 2002).

Wickens, C. D. Engineering Psychology and Human Performance. New York: Prentice Hall, 1993.