Driving safety in dementia: An updated systematic review of crash risk and driving impairment

Introduction: Dementia is a progressive neurodegenerative condition associated with declines in cognitive functions essential for safe driving. While on-road and simulator studies consistently demonstrate impaired driving performance, evidence regarding motor vehicle crash (MVC) risk remains mixed. This review synthesised contemporary evidence on the impact of dementia on real-world driving behaviour and crash involvement. Methods: A systematic search of CENTRAL, MEDLINE, Embase, Transport, PsycINFO, and Scopus was conducted in accordance with PRISMA guidelines. Quantitative studies published from January 2015 were included if they examined licensed adult drivers with clinically diagnosed dementia and reported outcomes related to MVC involvement, driving performance, or unsafe behaviour compared with cognitively healthy drivers. Methodological quality was assessed using the Joanna Briggs Institute tools. The review was registered with PROSPERO (CRD420251107288). Results: Thirteen studies met the inclusion criteria, including cross-sectional, cohort, and case–control designs. Findings for MVC involvement were heterogeneous: population-based studies generally reported no increased crash risk, whereas studies of medically referred drivers indicated elevated risk in selected subgroups. In contrast, studies examining driving errors and unsafe behaviours consistently demonstrated poorer performance among drivers with dementia, particularly in cognitively demanding situations such as hazard response and intersection negotiation. Naturalistic studies further identified persistent unsafe events during everyday driving, even among individuals adopting compensatory strategies in early disease. Conclusions: Dementia is associated with clinically meaningful impairments in driving behaviour and performance, evident even in the early stages of the disease. Differences in exposure, self-regulation, and regulatory processes largely explain variability in MVC findings. A multidimensional approach integrating MVC, performance-based, and naturalistic data is required to inform fitness-to-drive decisions. Practical applications: MVC involvement alone is an insensitive safety indicator. Performance-based and naturalistic measures provide more sensitive markers of impairment, supporting earlier risk identification, targeted intervention, and the development of in-vehicle monitoring and assistive technologies to enhance safety and prolong safe mobility.