Exploring the occupational fatigue risk of short-haul truck drivers: Effects of sleep pattern, driving task, and time-on-task on driving behavior and eye-motion metrics

Driver fatigue is the leading cause of truck-related accidents. The most significant occupational fatigue factors among short-haul truck drivers are sleep patterns, the round-trip driving task, and the time-on-task. However, the underlying mechanisms of these influential factors remain unclear. This study aims to explore the interactive effects of sleep patterns, driving task, and timeon-task on driving behavior and eye-motion metrics among short-haul truck drivers. We obtained test data from eleven professional short-haul truck drivers, with each driver participating in a three-day test under the conditions of two driving tasks and three different sleep patterns. We applied three-way repeated-measure ANOVA and non-parametric tests to analyze the data. The results reveal that: (1) violation of sleep-related legal requirements, insufficient sleep, and unreasonable time-on-task can have negative effects on short-haul truck drivers' vigilance and driving performance; (2) both driving task and sleep pattern contribute to driver fatigue, and the interaction of time-on-task and sleep pattern exacerbates driver fatigue more than the effects of any single factor alone; and (3) short-haul truck drivers who are sleep deprived exhibit short periods of controlled compensatory behavior during the outbound task, and sleepiness is more prevalent during the inbound task compared to the outbound task due to the monotony and low workload of the driving process. These findings provide theoretical and practical guidance for transportation industry managers to strengthen company-wide fatigue-related regulations, ensure adequate sleep for drivers via regulations, and optimize work schedules to improve safety outcomes of short-haul truck drivers.