Abstract for: Modelling the dynamics of mental workload and fatigue in safety-critical monitoring roles

In complex safety-critical systems, mental fatigue resulting from high levels of stress or boredom during monitoring tasks may lead to a higher risk of human errors and eventually accidents. However, the estimation and quantification of the operator’s mental workload have been challenging. We present a dynamic model of the suboptimality of workload and its interaction with fatigue through time in safety-critical monitoring roles. Using the context and data of the Traffic Controllers (TC) in the Belgian railway network, we have set to examine the dynamic hypotheses of mental fatigue affecting the workers’ overload and underload thresholds of TCs and consequently their comfort range of workload through time. The simulated model results show that 85-86% of work-hours in the morning and afternoon shifts are in the comfort range, in contrast with only 59% of the work hours in the night shift. This is due to the large portion of underload work-hours in the night shift, which brings about accumulated fatigue and boredom, resulting in the comfort range shrinking with an increased pace. Finally, our model takes the first leap to utilize simulation models and quantify the suboptimality of workload by considering the changes in the operator’s mental fatigue through time.