Schedule variability linked to fatigue and human factors incidents in new US Department of Transportation, Federal Railroad Association study.
In April 2014, the US Department of Transportation’s Federal Railroad Association (FRA) released a new report which examines a link between work shift start time variability and an increased risk of human factors accidents.
Their research concluded that in fact, the greater the inconsistency in the time of day works shifts are scheduled to start, the greater the level of worker fatigue and associated accident risk.
To assist in reaching these conclusions, Fatigue Science’s Fatigue Avoidance Scheduling Tool (FAST) was used to measure the level of fatigue in various work schedule scenarios. The FRA researchers used a FAST score below 90  to determine if fatigue was present, and then measured the amount of time workers spent below that criterion during their working hours.
Where schedules (during which an accident had occurred) exhibited a high rate of start time variability, FAST demonstrated the workers were spending as much as 50-60% of their time below the fatigue score criterion that was set for this study.
The report concludes:
Fatigue, as measured by the FAST score, was also shown to be a function of start time variability. While it was previously demonstrated that fatigue was a general function of sleep and work schedules (Raslear et al., 2011), this report extends that finding to specify start time variability as a critical aspect of work schedules when considering fatigue and the probability of an accident.
- FAST technology is trusted by the US Department of Transportation, Federal Railroad Administration as a tool for accurately predicting fatigue and levels of fatigue in their work schedules
- Fatigue is not only a factor for night shift or rotating shift workers
- Day shift workers can be subject to increased levels of fatigue if their work shift start times are inconsistent.
- Evidence-based decisions can be made that effectively reduce fatigue without adversely affecting operations.
1. The Fatigue Avoidance Scheduling Tool (FAST) uses scientifically-valid modelling algorithms to measure potential fatigue in work schedules – retrospectively for incident analysis, or in future schedules to optimize planning. FAST identifies that a score of 90 is associated with a 10% reduction in reaction time and 1.5x increased likelihood of a long lapse (or microsleep) – these associated performance changes increase as the FAST score for a schedule roster or worker lowers.