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Cognitive Distraction, Life Stress and Crash Risk

By Lisa Dorn: Founder, PsyDrive

What is Cognitive Distraction?

Distraction is defined as the diversion of attention away from activities critical to safe driving towards a competing activity. Driver distraction can stem from three sources: visual (eyes off the road), manual (hands off the wheel), and cognitive distraction. Cognitive distraction is anything that distracts your mind while driving (mind off the road). Whilst visual and manual distraction can be easily observed with the use of in-vehicle cameras, cognitive distraction is not possible to observe at all. For this reason, many fleet-based organisations are failing to consider the risks of cognitive distraction on crash risk.


Cognitive Distraction and Stress

One of the main sources of cognitive distraction is stress. Life stress can lead to drivers becoming preoccupied by thoughts about stressful encounters and situations. Rumination and worry are different forms of cognitive activity that impair performance in many ways. Intrusive thoughts about what’s going on in your life have been found to particularly impact on driving performance when the task is not demanding (1). Here, drivers have more spare attentional capacity to focus on their troubles such as relationship problems or financial worries. These life stress situations can lead to a driver’s attention being directed towards processing emotions rather than the road and traffic environment.


During a period of personal turmoil, drivers can become preoccupied with their worries, and this can take up limited resources in working memory. Working memory is an essential cognitive skill for safe driving. It allows drivers to hold a small amount of information temporarily, such as remembering the position of a following vehicle whilst moving lanes. When a driver is cognitively distracted by stressful life events, attentional resources can be diverted away from the driving task leading to errors, lapses of attention and crashes.

Life Stress and Crash Involvement

Several studies report that life stress increases the risk of crash involvement. Early findings report that drivers who had been killed in at-fault crashes had experienced significant social stress during the 12-months preceding the fatal crash compared with a matched control group. Drivers were five times more likely to cause a fatal crash compared with drivers without such stress (2). In a study of 410 drivers who had been involved in divorce proceedings over a seven-year period, it was found that crash involvement and traffic violations were significantly higher for the divorced drivers than for the wider driving population (3). The study found that the percentage of participants involved in crashes and traffic violations steadily rose in the six months immediately prior to filing for divorce, reached a peak within three months after filing, then declined. In later studies retrospective accounts from drivers involved in serious motor vehicle crashes have been used. These studies have found that participants who had been involved in marital separation or divorce within the year prior to the crash were up to four times more likely to be at-fault than other drivers (4, 5).


Safety Culture and Driver Stress Management

The research in this field suggests that fleet-based organizations need to do more to manage the risk of stress on crash involvement. Management practices and management concern for employee well-being means that vulnerable drivers can be identified, and interventions put in place. Organizations should take steps to increase awareness of the carryover effects of life stress on driving performance and identify life stress problems amongst their drivers. Improving management safety practices in this way communicates the company’s attitude to safety and improve the safety culture. Well-being policies such as these are indicative of an organisation that wants to develop a safety culture (6).


Developing your knowledge and skills in Human Factors

The third module of Level 2 of the accredited Human Factors and Road Risk Management programme covers the effects of stress on driver behaviour. Road safety practitioners learn new models and theories on the Human Factors for managing road risk. The programme is delivered live over 2 full days by Dr Lisa Dorn and includes approximately 15 hours of learning material including a pre-read workbook. The course encourages active, value-driven discussions and tailored to the specific interests of the delegates attending.


The next course runs on 23rd and 24th May 2024. For more information and other dates, click here: -


Book your place by completing the form here: -



  1. Matthews, G. (2002). Towards a transactional ergonomics for driver stress and fatigue. Theoretical Issues in Ergonomic Science, 3, 195-211.

  2. Brenner, B., & Selzer, M. L. (1969). Risk of causing a fatal accident associated with alcoholism, psychopathology, and stress: Further analysis of previous data. Behavioral Science14(6), 490-495.

  3. McMurray, L., (1970). Emotional stress and driving performance: the effect of divorce. Behavioural Research in Highway Safety 1, 100–114.

  4. Lagarde, E., Chastang, J., Gueguen, A., Coeuret-Pellicer, M., Chiron, M., Sylviane, L., (2004). Emotional stress and traffic accidents: the impact of separation and divorce. Epidemiology 15 (6), 762–766.

  5. Legree, P.J., Heffner, T.S., Psotka, J., Martin, D.E., Medsker, G.J., (2003). Traffic crash involvement: experiential driving knowledge and stressful contextual antecedents. Journal of Applied Psychology 88 (1), 15–26.

  6. Neal, A., Griffin, M., & Hart, P. (2000). The impact of organisational climate on safety climate and individual behaviour. Safety Science, 34, 99–109.




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