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You are here: Home › Mind Tactics › Questions from the Field › Adequate sleep needed to be safe while driving

Adequate sleep needed to be safe while driving

How much sleep is needed for maintaining adequate performance levels while driving commercial vehicles?

From the Field

I'm in the transportation industry and I'm looking for good scientifically based information on sleep and the amount needed for maintaining adequate performance levels while driving commercial vehicles. The FMCSA is trying to determine the appropriate hours of service rules for commercial vehicles. Unfortunately, there seems to be little scientific basis for their reasoning; instead they are in the middle of a special-interests tug of war. I thought the U.S. military might be a very good source of information on this because they should be interested in both sides of the issue. That is, maintaining adequate levels of performance while getting maximum productivity. Is there any information you can give me or point me in the right direction? I'm especially interested in any science on the subject that is verifiably free of insurance industry funding or personnel.

HPRC's Answer

The research around this question provides information on performance during sustained periods of wakefulness, not so much around the exact amount of hours of sleep are needed to perform well, since individuals can vary widely in performance responses to sleep loss. Prolonged wakefulness (lack of sleep, in other words) while performing tasks that require increased vigilance has a tremendous effect on cognitive performance (Van Dongen, et al., 2003), visual perceptual, complex motor, and simple motor performance, (Russo, et al., 2005), and decision-making (Kilgore, Balkin, and Wesensten, 2006). Tasks that require sustained alertness, like driving commercial vehicles, are most sensitive to sleep debt and sleep inertia2. So those performing this activity should adhere to standard sleep recommendations (six to eight hours/day). Studies indicate that between 18-25 hours of wakefulness showed performance impairments (Lamond and Dawson, 1998) and variations in reaction times (Doran, Van Dongen, and Dinges, 2001; Dawson and Reid, 1997) similar to having a blood alcohol content of 0.10%—well above the legal limit in all states. Thus, getting less than six hours/day sleep would increase the chances of making a fatal performance error akin to driving while intoxicated. Based on the literature, getting the recommended 6-8 hrs/day of sleep3 facilitates road safety and maximum productivity.

An important consideration around your question is the time of day in which the task is being performed—the amount of sleep is only half the story. In a 24-hour cycle, our bodies are guided by predictable patterns (circadian rhythms) that influence alertness and, subsequently, performance. So for example, while six hours of sleep may be adequate for maintaining performance during an eight-hour drive spanning 0900-1700 hrs, it might not be enough to sustain performance for a drive from 2400-0800 hrs (depending also on individual differences in resilience and effects of sleep loss). So the question of the recommended sleep is highly variable.

In addition to the citations referenced in the HPRC article titled “How much sleep does a Warfighter need?” are the materials listed under the References tab that go into more detail about the impact of sleep debt on performance.

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  1. The information in this response is based mainly on military operations and is not intended for specific civilian activities. Keep in mind the context of military environments. There is an expectation to engage, protect, and survive.
  2. Sleep inertia” is a term that is used to describe a state of confusion, disorientation, and delayed response.
  3. Napping is a common countermeasure that is thought to make up for sleep debt. Napping does not make up for lack of continuous sleep, but it is better than no sleep at all. For more information on countermeasures, see here.

References

References and Resources

1.     Effects of Partial and Total Sleep Deprivation On Driving Performance Factsheet (1999)

2.     Fatigue and its Effect on Performance in Military Environment (2007)

3.     Sustained Carrier Operations: Sleep Loss, Performance, and Fatigue Countermeasures (1997)

4.     Neurocognitive Consequences of Sleep Deprivation (2005)

5.     Behavioral and Physiological Consequences of Sleep Restriction (2007)

6.     Effect of Drowsiness on Driving Performance Variables of Commercial Vehicle Drivers (2009)

7.     The impact of sustained wakefulness and time-of-day on OSPAT performance (2005)

8.     Qualitative similarities in cognitive impairment associated with 24 h of sustained wakefulness and a blood alcohol concentration of 0.05% (2005)

9.     Sleep/Wakefulness Management in Continuous/Sustained Operations, NATO (2002)

10.  Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night (1997)