Multivariate analysis of age-related driver ability and performance deficits

A computerized measure of 22 visual, attentional, perceptual, cognitive and psychomotor abilities and a structured road test were administered to 407 elderly drivers age 62 and above. Approximately two-thirds of the sample ha d been referred to licensing agencies on the basis of observed unsafe incid ents and the remainder were volunteers free of reported incidents. Signific ant correlations (r = 0.4-0.5) were found between unsafe driving incidents and deficiencies in attentional, perceptual, cognitive and psychomotor cate gories and 0.3 for the visual. A total score based upon all ability measure s correctly identified 80% of incident-involved, while misidentifying only 20% of the incident-free drivers. Unsafe driving incidents evidenced signif icant but small positive correlations (r = 0.1-0.2) with road test errors i ndicative of skill deficiencies but not with errors in routine safe driving practices. Substantial examiner differences attenuated relationships invol ving road performances, and correlations with skill-related performances ro se (r = 0.2-0.3) when these effects were partialled out. Intercorrelations among measured abilities were high, indicating the need for caution in inte rpreting reported relationships between individual abilities and unsafe dri ving incidents. The authors also caution against interpreting correlations found in highly selected samples as representing the magnitude of relations hips in the population at large. (C) 1999 Elsevier Science Ltd. All rights reserved.