Road Test and Naturalistic Driving Performance in Healthy and Cognitively Impaired Older Adults: Does Environment Matter?

Objectives To relate the standardized road test to video recordings of naturalistic driving in older adults with a range of cognitive impairment. Design Cross-sectional observational study. Setting Academic medical center memory disorders clinic. Participants One hundred three older drivers (44 healthy, 59 with cognitive impairment) who passed a road test. Measurements Error rate and global ratings of safety (pass with and without recommendations, marginal with restrictions or training, or fail) made by a professional driving instructor. Results There was fair agreement between global ratings on the road test and naturalistic driving. More errors were detected in the naturalistic environment, but this did not affect global ratings. Error scores between settings were significantly correlated, and the types of errors made were similar. History of crashes corrected for miles driven per week was related to road test error scores but not naturalistic driving error scores. Global cognition (Mini-Mental State Examination) was correlated with road test and naturalistic driving errors. In healthy older adults, younger age was correlated with fewer errors on the road test and more errors in naturalistic driving. Conclusion Road test performance is a reasonable proxy for estimating fitness to drive in older individuals' typical driving environments, but differences between performance assessed using these two methods remain poorly understood and deserve further study. J Am Geriatr Soc 60: 2056-2062, 2012.