As people live longer and more older drivers give up their driving privileges, family, friends and public officials may find themselves asking, as it was in a popular film, "who's going to drive Miss Daisy?" The question could become a critical one as America ages, according to a new study*, which finds older men and women who outlive their ability or willingness to drive may be dependent on alternative transportation for more than a decade in later life.
"Hundreds of thousands of older people quit driving each year and must turn to alternative transportation. This change in status can create unforeseen economic and social burdens that need to be addressed in the same way we have encouraged people to think about planning for retirement and end-of-life care. I don't think sufficient attention has been paid to the transition from driver to non-driver in the aging population," says Dan Foley, M.S., a biostatistician at the National Institute on Aging (NIA) and lead author of the study, published in the August 2002 issue of the American Journal of Public Health .
Almost 10 percent of the nation's drivers are older than 65, and that percentage could increase rapidly in the next decade as the post-World War II "baby boom" generation begins to reach that milestone. In addition, a greater proportion of women age 65 or older is driving than in the past. By 2030, projections suggest one in five Americans will be 65 or older, and the number of people aged 85 and older—currently the fastest growing segment of the older population—could exceed 10 million. But in Foley's study, driving cessation peaked at about age 85, suggesting more of the oldest old may be dependent on other forms of transportation in the future.
The investigators analyzed data gathered in 1993 and 1995 as part of the NIA-supported Asset and Health Dynamics Among the Oldest Old (AHEAD) study. From this nationwide sample of people ages 70 or older, they assessed follow-up data on 4,996 men and women who were able to drive and had access to a car. Based on a statistical analysis, these drivers represented approximately 13.7 million Americans aged 70 or older who were driving in 1993, the baseline year. Overall, 82 percent of men and 55 percent of women in this age group drove that year. Driving prevalence declined with age, ranging from 88 percent of men in their early 70s to 55 percent of those 85 or older. Among women, about 70 percent drove in their early 70s compared to 22 percent still driving at age 85 or older.
Two years later, 7 percent of the drivers had died. Another 9 percent were alive, but had quit driving for other reasons. Overall, these findings suggest that more than 600,000 people age 70 or older stop driving each year and become dependent on others to meet their transportation needs. About 400,000 older drivers die of all causes annually. Other than death, poor vision, memory impairment and an inability to perform one or more activities of daily living (bathing, dressing, eating, transferring between bed and chair, toileting, and getting around inside the home) were common reasons older people stopped driving.
"Driving skills are dependent on three areas of wellness: physical fitness, thinking clearly and seeing well," Foley says. "Whether a person can continue driving hinges on the severity of the disability or functional loss in one or more of these three areas. Over time, people seem to reach thresholds where they believe they can no longer safely drive."
Statistical analysis showed that the average number of years a person continued to drive—the driving expectancy—was significantly less than overall life expectancy. For instance, men and women who were still driving at ages 70 to 74 were expected to drive, on average, another 11 years. But these men were expected to live about 17 more years, and the women nearly 21 more years. This gap between driving expectancy and overall life expectancy means men in this age group who stopped driving were dependent on alternative transportation for an average of six years. For women, the gap translated into about 10 years dependence on other transportation modes.
At age 85, those still driving had a driving expectancy of about two years. But even at this age, men would have 4 non-driving years of life remaining and women nearly 6 years. Researchers found no differences in driving expectancy between urban and rural areas.
"Driving has an essential role in helping older men and women live independently. However, with age, a person's competence and confidence behind the wheel may erode to the point that quitting becomes an unfortunate necessity and dependence on other means of transportation becomes an inevitable reality," Foley says. "If we, as a society, fail to take steps to help older people prepare for and cope with this transition, then the goal of improving the quality of life in old age will be greatly compromised, both now and in the foreseeable future."
DJ Foley, JM Guralnik, and DB Brock are with the laboratory of Epidemiology, Demography, and Biometry at the National Institute on Aging., Bethesda, Maryland. HK Hemovitz is with Sytel, Inc., Rockville, Maryland.
The NIA, a component of the National Institutes of Health, leads the federal effort in supporting and conducting basic and clinical research on aging and the special needs of older people. For information about the NIA, visit the website at www.nia.nih.gov  . For free brochures and booklets about aging and health topics of interest to older people, call the NIA Information Center at (800) 222-2225.