Insidious safety threat of fatigue: Investigating construction workers' risk of accident due to fatigue

The construction industry is among the most hazardous occupations. Workers are expected to fulfill physically and mentally demanding tasks in construction environments while they are exposed to numerous safety hazards. The dynamic and demanding nature of construction activities makes workers vulnerable to experience levels of fatigue on a daily basis. Fatigue is ubiquitous among construction workers and has been frequently cited as an underlying cause of the accidents. Despite the high rates of accidents in construction, research has shown that most of them can be prevented if workers identify hazards and perceive the associated safety risks. However, the impact of fatigue on the two leading safety indicators (i.e., hazard recognition and safety risk perception) has not been empirically studied before in the construction industry context. Therefore, this study aims to fill this gap by investigating the impact of fatigue on construction workers' hazard recognition and safety risk perception. To achieve the research goals, 135 construction workers were recruited to participate in the study. A validated safety instrument and three subjective fatigue assessment scales were used to measure safety performance and fatigue levels of the participants, respectively. The analysis of the data showed statistically significant correlation (p-value<0.001) between fatigue and hazard recognition (rp=-0.58) and fatigue and safety risk perception (rp=-0.51). Linear regressions associated 37% of the variability in hazard recognition and 28% of safety risk perception with elements of fatigue. The findings revealed that among all aspects of fatigue, intershift recovery and acute fatigue have the most profound impacts on the safety performance of workers. A novel model was developed and tested to explain how construction workers' safety performance (i.e., hazard recognition and safety risk perception) are impacted by elements of fatigue. This study offers practical recommendations for construction professionals and practitioners to control and mitigate the undesirable influences of fatigue on workers. These recommendations are presented as the hierarchy of fatigue interventions in the order of most effective to the least effective including (1) Elimination, (2) Substitution, (3) Engineering Solutions, (4) Administrative Interventions, and (5) Personal Assistive Equipment (PAE).