Characteristics of an elderly driving population referred to a geriatric assessment center. A retrospective, case-control study was performed to determine the characteristics of elderly drivers referred to an outpatient geriatric assessment center. It was hypothesized that the driving population was operating at a higher cognitive and functional level than nondrivers. One hundred eighty-two subjects meeting the entry criteria were studied. Twenty-three percent of the subjects were driving at the time of their assessment. Compared to nondrivers, drivers were younger (P = .0001), were more likely to be male (P = .003), scored higher on a mental status examination (P = .0001), and were more independent in Physical and Instrumental Activities of Daily Living (P less than .0001). Despite these findings, the mean Folstein Mini-Mental score for drivers (23.7) was below normal; 40% of drivers were diagnosed as having Alzheimer's dementia at the time of their evaluation, and over 26% of the drivers needed help with either dressing or bathing. The frequency of impaired elderly drivers in this referral setting was high. The authors conclude that conditions that affect the driving task are common in geriatric assessment centers. Prospective studies of elderly drivers are needed to answer the difficult question of who among the elderly should drive. 