PSYCHOMETRIC EVALUATION OF CARS: A BRIEF SCREENING INSTRUMENT FOR DRIVING SAFETY

Abstract

Abstract Driving is critical to mobility, autonomy, freedom of choice, and engagement for older adults, but many eventually stop driving. While poor health often eventually leads to driving cessation, some drivers do not realize that their driving is impaired. The 4-item CARS instrument of driving safety has been created to serve as a screening tool by health professionals during assessments and routine appointments (Curl, 2014). To assess the construct validity of CARS, data were collected in 2015-2016 by The Knight Alzheimer’s Disease Research Center from cognitively impaired (N=42) and cognitively healthy participants (N=229), as well as “collateral sources” who answered the CARS items about the respondents’ driving. Vision problems and cognitive impairment, both known predictors for driving problems, were correlated with CARS scores. Results indicate that worse eyesight in the right eye is correlated with higher CARS scores (Spearman rho = -.17, p<.01), but not the left eye. Poor eyesight (i.e., less than 20/40 vision) was correlated with higher CARS scores (Spearman rho = .12, p<.05). However, cognitive impairment (very mild/mild dementia vs. healthy cognitive functioning) was not statistically significant. Total CARS scores were moderately correlated for respondents and their collateral sources, r = .32, p<.01. Results indicate that this instrument may be more useful as a tool for initiating difficult conversations about driving safety than for identifying older adults who are at higher risk for negative driving outcomes. Future research is needed to identify additional/alternative items with greater psychometric support.