Fatigue and Road Safety: A Critical Analysis of Recent Evidence

  • Published: Department for Transport, Road Safety Web Publication No. 21 (2011)
  • Authors: Jackson, P., Hilditch, C., Holmes, A., Reed, N., Merat, N. & Smith, L.
  • Date Added: 29 Dec 2013
  • Last Update: 12 Feb 2016
  • Format: pdf


To provide a comprehensive and critical review of the literature that synthesises the evidence relating to fatigue and road safety.


The Department for Transport research specification identified a list of research questions that were to be addressed by this project. These questions were distributed between the three teams collaborating on the project: Clockwork Research, the University of Leeds and the Transport Research Laboratory (TRL). Each team worked independently to identify and critically evaluate the key sources relevant to their research questions, according to criteria agreed with the client at the inception meeting.

Key Findings:

  • There had been little research up to the date of the study conducted in the UK to explore this issue.

  • Current understanding of the prevalence of driver fatigue, its impacts on casualty rates, and on drivers’ actual behaviour is based on partial information, historic data or international research.

  • There is now considerable evidence that the effects of fatigue impact upon performance prior to the onset of micro-sleeps and/or lapses.

  • Fatigue is associated with a progressive escalation of performance variability and the deregulation of neurocognitive performance, of which micro-sleeps are an extreme symptom.

  • Young, male drivers are over-represented in driver fatigue crashes. However, it is also the case that this group may be more at risk due to higher exposure rates and lifestyle factors.

  • Obstructive sleep apnoea is very much under diagnosed and compliance with treatment is poor. Commercial vehicle drivers are known to be at higher risk of having obstructive sleep apnoea.

  • Drivers of large goods vehicle are involved in a disproportionately high number of fatigue-related accidents.

  • Understanding of the link between fatigue and work-related road safety in the UK suffers from a lack of information.

  • Many drivers continue to drive tired despite being aware of their tiredness placing themselves and others at risk.


Sleep, driving, performance, simulator, psychological factors, physiological factors, obstructive sleep apnoea, attitudes, countermeasures


A comprehensive review of evidence surrounding the issue of driver fatigue undertaken on behalf of the Department for Transport. This study is one of six used as a core guide to the development of this synthesis.