Isolating Risk Factors for Crash Frequency among Older Drivers

Abstract

By the year 2024, 25% of drivers in the U.S. will be over the age of 65. Older drivers have more crashes and fatalities per mile driven than any other adult age group. Although driving is a highly visual task and vision impairment is more prevalent in the elderly, previous research has failed to identify visual factors which are strongly associated with increased crashes in the elderly. Using a comprehensive approach to assess several aspects of visual processing in a large sample of older drivers, this study has identified a measure of visual attention that had high sensitivity (89%) and specificity (85%) in predicting which older drivers had a history of crash problems, a level of predictability unprecedented in research on crash risk in older drivers. The “useful field of view”, as it is called, measures the spatial area within which an individual can be rapidly alerted to visual stimuli. Older adults with substantial shrinkage in the useful field of view were six times more likely to have incurred one or more crashes in the previous five year period. By comparison, visual sensory function, cognitive status, and chronological age were poor predictors of crash involvement. This study suggests that policies which restrict driving privileges based solely on age or on stereotypes of age-related declines in vision and cognition are scientifically unfounded. With the identification of a visual attention measure highly predictive of crash problems in the elderly, decisions on the suitability of licensure in the older adult population can be based on objective, visual-performance-based criteria.