Four hours duration acts as the safety threshold for driving fatigue management

Driving fatigue is widely recognized as one of the primary causes of traffic accidents and injuries, particularly during prolonged driving scenarios. It is therefore crucial to investigate the fatigue process during driving in order to establish guidelines and standards for determining optimum driving time. Previous research has shown a correlation between fatigue and visual involuntary attention, which is a critical function for human beings to detect potential hazards and ensure self-protection. In this paper, we propose a visual involuntary brain functional experiment to incorporate visual involuntary attention into driving fatigue assessment, wherein we record various responses such as performance accuracy, reaction times (RT), etc. We also recorded the hemodynamic changes of the prefrontal lobe using fNIRS. A total of eight volunteers participated in a 7-hour simulated driving session, during which the visual involuntary brain functional experiment was conducted every hour for a total of eight times. The results of the study indicate a clear degradation of driving performance over time. The fNIRS results demonstrate that the midline of the prefrontal lobe exhibits the strongest activation, which suggests that participants’ cognitive ability is impacted by fatigue. The channel with the maximum activation demonstrated a strong negative correlation between Δ[HbO
2
], Δ[tHb], and accuracy/RT, respectively, for the majority of participants. Based on the behavioral results, a fast phase was identified in drivers’ behavior, which began approximately four hours into the driving session and rapidly declined. This observation indicates that the optimal maximum continuous driving time should be less than four hours. The findings on the four-hour threshold for driving may serve as a reference for long-distance drivers seeking to avoid traffic accidents caused by fatigue.