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Road Management & Engineering Journal
Copyright © 1997 by TranSafety, Inc.
March 1, 1997
TranSafety, Inc.
(360) 683-6276
Fax: (360) 335-6402

Texas Liable for Injuries Caused by Rotating Traffic Light
Licensing Older Drivers II
Licensing Older Drivers III

Licensing Older Drivers--Part I

The number of older drivers will grow an estimated two-thirds by 2030. Reflecting this trend, drivers over 85 years of age increased their use of private automobiles compared with other modes of transportation by more than 10 percent from 1977 to 1983. The per-mile crash rate for this group is nearly as high as the rate for teenagers; thus, according to A. James McKnight of the National Public Services Research Institute, an increase in miles driven by seniors "presents an obvious threat to the safety of the motoring public." McKnight wrote these words in his introduction to the Transportation Research Board's Circular Number 429: The Licensing of Older Drivers published in July 1994.

In September 1993, A. James McKnight chaired a meeting of the Operator Education and Regulation Committee of the Transportation Research Board. Thirteen researchers and practitioners addressed this meeting on topics related to the process of licensing drivers, especially elderly drivers. Each presentation and resulting paper included sections covering: (1) the nature of a specific concern in the licensing of elderly drivers, (2) the needs to be addressed by a process designed to alleviate the concern, and (3) the actions to take in resolving the concern. The authors wrote about three major processes of driver licensing, and the circular presented the papers in three separate sections:

  1. Screening Processes,
  2. Corrective Processes, and
  3. Support Processes.

This issue of the TranSafety Reporter summarizes the five papers on screening processes. The next two issues will include articles on corrective and support processes.


In these articles dealing with assessing the nature and extent of age-related deficiencies, the authors discussed five screening methods:

  1. Driving performance,
  2. Functional capabilities,
  3. Medical evaluation,
  4. Vision screening, and
  5. Use of traffic records.

Screening for Driving Performance by Carmella M. Strano, Moss Rehabilitation Hospital

As drivers age, visual-perception skills worsen and information processing slows. Although research has not shown a cause-and-effect relationship between age-related deteriorations and an increased incidence of automobile crashes, Strano observed that older drivers show evidence of "poor judgement in making a left-hand turn, drifting within the traffic lane, and an inability to change behavior in response to an unexpected or rapidly changing situation." Development of behind-the-wheel tests that elicit these problem behaviors is needed.

To decide which drivers suffer from conditions that require such testing, licensing agencies must have referrals from physicians and eye-care specialists. Pennsylvania is one state that has a "physician's reporting law" requiring physicians to report "disabilities that may affect driving ability." Some physicians, however, are reluctant to jeopardize their relationship with a patient by making such a referral, and many elderly drivers do not want to appear at a driver licensing agency because they fear having to take a knowledge test in addition to a performance test. Therefore, Strano suggested hospital- based, behind-the-wheel testing that would be more well-received by medical professionals and elderly patients.

The author recommended: (1) uniform national reporting requirements for medical professionals, (2) a study to find how feasible it would be for driver licensing agencies to contract with rehabilitation specialists for performance testing, and (3) development of better performance tests with an interim measure of testing all drivers over a certain age each time they renew their licenses.

Screening of Drivers' Functional Capabilities by Loren Staplin, Ph.D., The Scientex Corporation

Although the report did not include a citation reflecting the source of the statistics, Loren Staplin asserted that:

[e]stimates of the variance in accident involvement accounted for by operator inattention or information processing deficiency range from 40 up to 70 percent. In other words, an individual's "functional capability" may be as important a predictor of accident risk as roadway, traffic, and weather conditions combined plus performance on other, traditional measures of driver capability such as the battery of vision tests used in most states.

Appropriate and timely control of a vehicle result from a combination of perceptual, cognitive, and psychomotor functions. Aging is associated with increasing deficits in these functions. Elderly drivers, especially in the 75-and-over age group, have difficulty separating information they need for safe driving from the visual clutter that confronts all drivers. In addition, slower decision-making skills contribute to increased difficulty avoiding a collision in a rapidly changing driving situation. Staplin emphasized, however, that many elderly drivers show skills equivalent to motorists in early middle- age. Therefore, screening processes are necessary to identify which older drivers are at higher risk of crashes.

Tests that measure speed of response, ability to judge a safe turning gap in traffic, and appropriate maneuver decisions within the complex context of driving situations are only the beginning. Differences in functional capability revealed by these tests must be correlated with crash records to learn which functional deficiencies are causal in crash situations. It will take considerable research and public relations to convince the driving public that licensing agencies should restrict driving privileges based on frequently unnoticed cognitive difficulties. Revoking or limiting driving privileges results in a loss of mobility and dignity for elderly drivers, and it is not a move to be made without sufficient basis.

To develop screening procedures that identify at-risk drivers without discriminating by age, Staplin recommended: (1) promoting broad awareness of research on the cause-and-effect relationships between cognitive deficiencies and crashes, (2) gathering real-time data showing those relationships, (3) validating that data with crash statistics, (4) standardizing crash reporting to facilitate gathering data, and (5) developing valid and reliable screening tests for determining functional abilities.

Medical Evaluation by Mary L. Vinsant, M.D., M.P.H., North Carolina, Driver Medical Evaluation

Citing high crash rates in the rapidly growing elderly driving population, Vinsant noted that most states do not require physicians to report to licensing agencies psychomotor, visual, and cognitive deficiencies that may affect driving. Police officers, family and friends, court representatives, and personnel from agencies that work with the elderly sometimes refer older drivers to licensing personnel. Frequently, however, primary care physicians are in the best position to know a driver's medical history and recognize health problems that might cause driving difficulties. Such problems may include: impaired hearing and vision, slowed reaction times, heart problems, lung disease, diabetes, neurologic conditions (e.g., Alzheimer's disease), arthritis, or alcohol abuse.

Physicians need valid, reliable tools to diagnose functional deficiencies. Maine and Utah have physicians' guides to help in these diagnoses. When physicians detect diseases that may impair driving ability, they must also predict whether the condition will have a negative effect on driving. The likelihood that a seizure will recur, the frequency and intensity of arthritic flare-ups, or the degree of distraction caused by leg stiffness will determine the extent of limitation such conditions place on driving. Patients with dementia are unlikely to be able to decide for themselves how severely impaired their driving is; the physician will need to make a judgment. Recommendations from physicians, evaluations by occupational therapists, and advice from the state Medical Advisory Board combine to help driver licensing agencies make decisions on licensure.

Physicians should not have to make such decisions in isolation. Therefore, Vinsant named five actions that would help doctors in making recommendations: (1) research to learn the effect of medical conditions on driving ability, (2) development of tools to find the extent of impairment at various stages of disease, (3) awareness of research on driver risk as it relates to disease, (4) access to driving records, and (5) supplementary information from family members on a patient's medical history.

Vision Screening by David Shinar, Ph.D., Ben Gurion University of the Negev

Visual acuity deteriorates at an earlier age and more quickly than other perceptual-motor skills, but deterioration is still so gradual that many people are unaware of the extent of impairment. As driver licensing agencies work to find out the extent of visual impairment in older drivers, they are reluctant to use time-consuming, expensive tests, especially since there is little consensus on what tests are best and what level of visual acuity is good enough for driving. Shinar emphasized that the independence of driving is important to older citizens--who often stop visiting, shopping, and even going to church if they cannot drive.

Recognizing that all of us will someday be older drivers seeking the tolerance of younger motorists, Shinar called for public education on "the actual low frequency of older driver crashes," the significance of driving mobility to older drivers, and the effectiveness of seniors' self-limiting behavior in preventing crashes. He suggested older drivers be educated in ways they can detect their own vision problems and compensate for driving difficulties caused by those problems. This could be accomplished through a self-awareness test kit, promoted by organizations whose membership is largely older people. The same organizations could emphasize the importance of annual or biannual vision tests for eye diseases that affect driving (e.g., cataracts, glaucoma, etc.).

Shinar suggested research on how visual deficiencies relate to the ability to perform driving maneuvers and to crash involvement. Research on compensating behaviors for seniors with visual deficiencies is also important. States should share information on successful alternate programs for elderly drivers. In addition, each state should set up a panel to recommend guidelines for departments of motor vehicles to use in establishing what factors suggest the need for further vision testing, what tests to use, and what type of restrictions to place on driver licenses. Restrictions might permit drivers to go no more than a specific distance from home or might limit their driving to certain speeds, times of day, or road types.

Use of Traffic Records to Identify High Risk Drivers by Carol L. Popkin, M.S.P.H., North Carolina Health and Natural Resources Department

Departments of motor vehicles need a cost-effective way to identify high-risk older drivers. Older drivers are the fastest-growing segment of the population, and their driving performance varies greatly from driver to driver. Research shows that the crash rate of older drivers begins to increase about age fifty and experiences a sharp increase about age seventy. On the other hand, many older drivers do not have impairments that affect their driving, and others compensate effectively for driving problems they develop. Routine drivers' tests might identify elderly persons whose driving capabilities are impaired; however, to save money on retesting, many states are not requiring drivers with good driving records to retest each time their licenses expire. Thus, it may be as many as ten years between drivers' tests. Furthermore, when older drivers have to take driving tests, they generally pick their "best" day to go in, and the results may not reflect their driving problems. Some states are beginning to use age data combined with crash statistics to decide what drivers should have shorter times between license reexaminations.

To find out if crash records are a feasible way to identify high-risk drivers, researchers need to: (1) determine how available crash records are, (2) find out what portion of the at-risk population such data will identify, and (3) analyze crash patterns to see if some types of crashes are better predictors than others of higher crash risk. Popkin cited M.A. Gebers and R.C. Peck's 1992 study (The Identification of High Risk Older Drivers Through Age-Mediated Point Systems) that found "older drivers exhibit a steeper increase in future crash risk at successive prior incident levels, relative to drivers in general." Based on this research, California, which requires retesting for anyone involved in a fatal crash or three or more crashes in one year, now requires drivers over 70 to retest if they are involved in two or more crashes in one year.

Popkin recommended further investigation into effective ways to use crash statistics as part of a program to identify high-risk older drivers. In addition to crash counts, the details of the crash (roadway condition, time of day, location, fault) are important. Some crash patterns (e.g., the driver stopped in the middle of the roadway) may be better predictors of future crashes than others. Given that many older drivers involved in crashes have never had a crash before and may not have another one during the following year, crash records will identify only a few high-risk older drivers. However, using crash statistics may be an important part of a comprehensive program to identify high-risk older drivers.

Copyright © 1997 by TranSafety, Inc.

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