Investigating the impact of fatigue level on visual attention of heavy-duty truck driver: An eye tracking study

Fatigue driving is considered one of the main risk factors leading to truck-involved crashes. A significant correlation between fatigue driving and visual behavior has been established in previous studies. However, the relationship between visual behavior and fatigue levels, especially among truck drivers, has been seldom explored. Therefore, this study conducted a field driving test on heavy-duty truck drivers to assess their visual attention distribution when affected by fatigue. Fatigue levels were measured based on the Percentage of Eye Closure (PERCLOS), and the impact on eye movement was evaluated. The study found that an increase in PERCLOS led to a decrease in the percentage of glances toward the left-wing mirror and the right-hand side of the windshield. Similarly, the number of glances toward the left-hand side of the windshield and left-wing mirror also decreased with the increase in PERCLOS. These findings suggest that a higher level of fatigue results in reduced attention toward the left-wing mirror and windshield, with truck drivers' focus remaining at the front for longer periods, indicating a reduced alertness to road conditions. These insights could be valuable in monitoring fatigued drivers by examining the visual attention of heavy-duty truck drivers.