A socio-ecological model of drowsy driving in the UK: Are we there yet?

Despite its substantial contribution to road traffic collisions, injuries, fatalities, and associated economic costs, drowsy driving remains a persistent transportation safety and public health concern. Although there is substantial literature regarding sleepiness and fatigue in the context of driving, alongside policies, practices and safeguarding procedures, levels of drowsy driving appear to remain consistent, highlighting the need for a more integrated understanding of the factors influencing this behaviour. This narrative review synthesises interdisciplinary evidence from transportation, sleep science, psychology, occupational health, and public health. It examines the scale of drowsy driving, its contributing factors, and its emergence as a complex transportation behaviour shaped by interacting individual, social, and societal influences rather than solely by individual choice. Building on the reviewed evidence, a socio-ecological model of drowsy driving is proposed to integrate biological, behavioural, occupational, technological, and policy influences within a single conceptual framework. The review identifies key knowledge gaps and future research priorities and provides a framework to guide interdisciplinary transportation research, policy, and practice addressing drowsy driving and improving road safety.