Safe Transportation Research & Education Center

Many health problems, especially those associated with older age, can have an impact on an individual’s mobility. This paper addresses how specific functional limitations and medical conditions may be associated with driving status, while controlling for age and gender. This paper uses baseline data (N=2025) from a longitudinal survey of adults, ages 55 and older, the Study of Physical Performance and Age-Related Changes in Sonomans (SPPARCS). For the 35 selected medical conditions and functional limitations, this report presents the prevalence, the relative “risk” ratio (i.e., the risk that an individual with that condition no longer drives), and the attributable risk (i.e., the percent of ex-drivers with each condition). Compared to current drivers, ex-drivers had higher rates of physical limitations (ability to ascend one flight of stairs or walk three blocks), cognitive impairment, vision problems and stroke. The conditions with the highest relative risk included personal mobility limitations (such as the ability to transfer onto or from bed and the ability to use the lavatory) and decreased peripheral vision. The relative risks of medical conditions’ effects on driving status offer a perspective on individuals’ mobility choices, and the attributable risks offer a perspective on the most important causes of driving cessation in the elderly population.