4,000 people die in crashes involving large trucks and buses. NIOSH study results connect truck drivers’ sleep patterns to driving performance

Approximately 2.6 million workers are employed as drivers of large trucks in the United States. Each year, about 4,000 people die in crashes involving large trucks and buses – truck drivers and passengers, as well as other road users. 

Fatigued or drowsy driving is widely recognized as a contributor to fatal crashes involving large trucks. Stress associated with working as a truck driver (e.g., irregular schedules, long work hours, and economic pressures) may put these drivers at risk for insufficient sleep and/or irregular sleep behaviors or patterns.

A study done by NIOSH in collaboration with the Virginia Tech Transportation Institute examined sleep patterns of 96 commercial truck drivers during their non-work periods and evaluated the influence of these sleep patterns on subsequent truck-driving performance during work periods. Driving performance was measured by safety-critical events (SCEs), which include crashes, near-crashes, crash-relevant conflicts, and unintentional lane deviations.

The statistical analysis grouped each work shift into one of four distinct sleep patterns:

1. Moderate sleep averaging 6.7 hours: In general, sleep started in the middle of the non-work period and lasted approximately half of the non-work period.
2. Short sleep averaging 5.8 hours: Sleep started at the beginning of the non-work period and lasted on average for 44% of the non-work period.
3. Long sleep averaging 8.1 hours: In general, sleep occupied two-thirds of the non-work period.
4. Long sleep averaging 9.3 hours: Sleep occupied almost the entire non-work period, 93% on average.

Across all four sleep patterns, higher SCE risk was found among drivers who were male, had fewer years of truck-driving experience, or had higher body mass index (BMI). Pattern 2 shifts, which were characterized by shorter sleep time early in a non-work period, were associated with an increased rate of SCEs compared to Patterns 3 and 4, which had longer sleep periods. Pattern 2 shifts were also considerably less likely to have sleep during the time period between 1 and 5 a.m. compared to Patterns 1, 3, and 4.

Study results show the importance of drivers’ receiving adequate sleep the night prior to their driving and underscore the importance of providing drivers with sufficient sleep opportunities. The results of this study suggest that longer sleep duration has a measurable safety benefit by reducing SCE risk in the following shift.

Findings from this study highlight the importance of driver training and fatigue prevention among truck drivers. Prevention strategies include educating drivers on the safety benefits of adequate sleep, getting sleep between 1 and 5 a.m., and arranging sleep late in the non-working period if possible. More sleep tips are available in NIOSH’s Quick Sleep Tips for Truck Drivers .

Publication: Chen GX, Fang YJ, Guo F, Hanowski RJ. The influence of daily sleep patterns of commercial truck drivers on driving performance. Accident Analysis and Prevention 2016; 91: 55−63.