Intersection Rules Subtest Timing as a Predictor of DriveSafe DriveAware Outcomes: A Pilot Study

Importance Intersection Rules Subtest timing is a potential predictor of the DriveSafe outcome score in DriveSafe DriveAware (DSDA) assessment. Objective To examine whether Intersection Rules completion time is associated with DriveSafe outcome within the DSDA assessment. Design Retrospective, observational pilot study using secondary data. Setting Australian metropolitan fitness-to-drive clinic. Participants Of 169 participants (median age = 80; 61.5% male), 104 categorised into non-pass group of DriveSafe subtest formed ‘cases’, whilst 65 who passed were ‘controls’. Outcomes and Measures Primary predictor: Intersection Rules Subtest completion time in seconds. Primary outcome: DriveSafe subtest outcome, categorised as pass/non-pass. Relationships analysed using logistic regression and receiver operating characteristic (ROC) curve analysis. Results Longer Intersection Rules Subtest time significantly predicted lower DriveSafe subtest outcome (non-pass) scores, with each additional 60 s increasing odds of failure by 93.7% (odds ratio [OR] = 1.94, 95% confidence interval [CI] [1.40, 2.68], p < .001). A ROC curve analysis revealed an area under the curve of 0.73 (95% CI: [.654, .807]). An optimal cut-off of 213.5 s showed high specificity (86.2%) (95% CI: [75.3, 93.5]) but modest sensitivity (48.1%) (95% CI: [38.2, 58.1]) for a non-pass result. Conclusions and Relevance Intersection Rules Subtest completion time was associated with DriveSafe outcome in this pilot study. The current findings support future study of this timing metric, which may have potential as a clinical decision-support indicator, a ‘Detect and Pause’ step, after prospective validation and DSDA protocol sequence modification.