Fatigue (safety)
![Why the hours of service are important: a graph outlining the relationship between number of hours driven and the percent of crashes related to driver fatigue.Source: Federal Motor Carrier Safety Administration[1]](/Images/godic/202501/10/Hours_of_service_FMCSA_study.svg0243.png")
Fatigue is a major safety concern in many fields, but especially in transportation, because fatigue can result in disastrous accidents. Fatigue is considered an internal precondition for unsafe acts because it negatively affects the human operator's internal state. Research has generally focused on pilots, truck drivers, and shift workers.