Safety Issues

 
20
Mar

Sleep Patterns Influence Truckers’ Driving Performance

By: Guang X. Chen, Youjia Fang, Feng Guo, Richard J. Hanowski

Getting enough Zzz’s?

We all know that proper nutrition and exercise is needed to stay healthy, but getting enough sleep is just as important. Each year, about 4,000 people die in crashes involving large trucks and buses – including truck drivers, passengers, and others on the road. It is estimated that 10 to 20 percent of these crashes involved fatigued or drowsy drivers. Irregular schedules, long work hours, and economic pressures may put truck drivers at risk for lack of sleep or irregular sleep patterns

The Study

Researchers from the National Institute for Occupational Safety and Health (NIOSH), in collaboration with Virginia Tech Transportation Institute (VTTI), studied sleep patterns of 96 commercial truck drivers who drove over 735,000 miles. The researchers examined truck drivers’ sleep patterns during non-work periods. Then, they evaluated the influence of the sleep patterns in non-work periods on driving performance during subsequent work periods. Driving performance was measured by Safety-Critical Events (SCEs), which included crashes, near-crashes, and unintentional lane deviations.

As shown in the following table, truck drivers’ fell into one of four different sleep patterns:

Sleep pattern

Average sleep

% of non-work period

% with any sleep 1-5 a.m.

SCEs per 100 h driven

1

6.7 h

53

86

16.4

2

5.8 h

44

35

21.8

3

8.1 h

68

83

13.4*

4

9.3 h

93

89

13.7*

 

*SCE rate was significantly different from Pattern 2 (p-value <0.05).

Pattern 2, highlighted in orange, differs from the other 3 patterns in several ways: 
  • It had the shortest sleep – 5.8 hours on average.
  • Sleep made up the lowest percentage of the non-work period – 44% on average.
  • It had the lowest percentage of non-work periods with sleep between 1 and 5 a.m.
  • It had the highest rate of SCEs. In comparison to pattern 1, pattern 2 sleep occurred in the early stage of non-work periods, while pattern 1 sleep occurred in the late stage of non-work periods.

The researchers performed 1-to-1 comparisons among all sleep patterns. Two significant differences were found: compared to Pattern 2, Patterns 3 and 4 had significantly lower rates of SCEs. These results suggest that getting more hours of sleep, including getting sleep between 1 a.m. and 5 a.m., is associated with lower rates of SCEs.

In addition, findings from the NIOSH study suggest that male drivers, drivers with fewer years of commercial vehicle driving experience, and drivers with higher body mass indexes had significantly higher SCE rates than their counterparts respectively.


What you can do to prevent drowsy or fatigued driving


 Drivers: 
  • Get adequate sleep (at least 7 hours) before starting your work shift. 
  • Getting enough hours of sleep and sleeping between 1 a.m. and 5 a.m. is especially important.
  • Try some Quick Tips for Truck Drivers.

Employers:
  • Train drivers on the safety and health benefits of getting adequate sleep (employers can try the training module in the North American Fatigue Management Program, www.nafmp.com). 
  • Provide drivers with sufficient opportunities to get quality sleep during non-working periods.
  • Avoid scheduling work time or driving in the time period between 1 a.m. and 5 a.m.
For more information, visit NIOSH’s Long-Haul Truck Drivers and Motor Vehicle Safety at Work pages.
For more information about the study please see 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.

Acknowledgements

The naturalistic on-road study from which this data was collected was funded by the Federal Motor Carrier Safety Administration under Contract DTFH61-01-C-00049, Task Order # 23. The contracting officer's technical representative was Robert J. Carroll.

Disclaimer:  The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health or any government agency.   

Safety Issues is presented by the National Institute for Occupational Safety and Health (NIOSH) in partnership with the National Truckers Association (NTA).  NIOSH is the U.S. federal agency that conducts research and develops recommendations to prevent all kinds of occupational injuries and illnesses. NIOSH uses the results of its research to communicate prevention information to employers, workers, and others who are in a position to make changes to improve safety and health for workers. This month’s Safety Issues was contributed by the NORA Transportation Warehousing and Utilities Sector in cooperation with researchers from the NIOSH Long Haul Truck Driver Safety and Health Survey Team and the NIOSH Center for Motor Vehicle Safety. Further information can be found at the NIOSH LONG-HAUL TRUCK DRIVERS web page (www.cdc.gov/niosh/topics/truck/default.html) and Motor Vehicle Safety at Work (www.cdc.gov/niosh/motorvehicle).