Drawing errors but not drawing strategies: Discriminating safe from unsafe driving in commercial drivers and cognitively at-risk seniors

• The Vitals visuospatial working memory (WM) task discriminates safe and unsafe drivers. • Differences in drawing strategy could explain poor performance in unsafe drivers, not WM deficits. • Medically at-risk older and commercial drivers performed the Vitals and an on-road evaluation. • Safe and unsafe drivers differed on shape replication accuracy but not drawing strategies. • The best explanation for poor Vitals performance is therefore a WM deficit. The Vitals cognitive assessment tool is a battery of tablet-based cognitive and sensorimotor tasks which are used to predict safe or unsafe driving. One of the Vitals tasks is a visuospatial working memory task, which requires people to replicate a simple shape following a short delay. Previous evidence suggests that poor performance on this task is associated with cognitive impairment and risky driving, but this poor performance could have several possible explanations, including a working memory deficit, abnormal drawing strategies, or problems with motor execution. In this study, we recruited medically at-risk older drivers and healthy commercial drivers to perform the Vitals, as well as an on-road driving evaluation. Drivers who failed the on-road evaluation drew fewer correct shapes compared to drivers who passed, but did not show any differences in drawing strategy. At-risk older drivers who failed showed an increase in motor errors while producing the drawings, while commercial drivers who failed were slower to complete the task. This pattern of results excludes suboptimal drawing strategies as an explanation for poor performance, and also exclude motor errors while producing the drawings as an explanation for increased completion time. The best explanation for poor performance on the Vitals’ visuospatial working memory task is therefore a working memory deficit.