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Shift Patterns and Driver Fatigue

By Dr Lisa Dorn, PsyDrive: Founder

This is the fourth blog in our series to introduce the five modules delivered live for the Human Factors in Road Risk Management Programme accredited by the Chartered Institute of Ergonomics and Human Factors.


The Fatigue and Workload Module aims to explain the impact of fatigue and workload on road user behaviour. It is common for road users to be less aware and make mistakes after riding/driving for more than 2 hours. But effects can be seen much sooner, especially in combination with sleep deprivation and/or high workload. The types of roads being driven can impact on fatigue. For example, driving on a quiet motorway can induce higher levels of fatigue due to lower workload compared with driving in a built-up area in heavy traffic.


Fatigue due to prolonged driving and sleepiness (due to time of day or sleep loss) has a major effect on human performance including reduced vigilance, impaired attention, and slower reaction times. The contribution of fatigue and sleepiness to crash causation is most likely underestimated due to the lack of a standardised definition of sleep-related crashes and the extent to which fatigue and sleep-related crashes go undetected. However, when the body is at its lowest temperature between the hours of 2am and 6am, performance is at its worst. There is also an afternoon slump when we find it hard to stay vigilant. These performance effects can be seen in the distribution of crashes by time of day which tends to show three peaks: two during the early morning (at around 02:00-03:00 and 06:00-07:00) when traffic flow rates are low: one in the mid-afternoon (16:00-17:00) at a time of high traffic density.


Shift work is a source of fatigue and low levels of alertness and shift patterns commonly used in transport settings can disrupt established sleep patterns. Double shifts, changing shift patterns and excessive overtime can play havoc with your natural body clock. There is no ‘ideal’ shift pattern; it remains a compromise between conflicting requirements, but the body finds it easier to adapt to forward rotations and night shifts should be followed by days off where possible.


To find out more about fatigue and workload, book your place on Level 1 of the Human Factors and Road Risk Management Programme.



PsyDrive is a specialist provider of training for road safety professionals, research, assessment, and interventions for improved road safety.


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