SEATTLE, Wash. — Drivers who understand the causes of fatigue and how to manage it will be safer, more productive workers and may even live longer.

That according to Dr. Ronald Knipling, author of Safety for the Long Haul and the guest on a recent Webinar sponsored by Zonar.

Knipling said professional drivers, as a whole, are an unhealthy lot, and much of that can be blamed on fatigue.

“The health problems associated with fatigue are as big as the safety problems,” he said. “Commercial drivers are among the unhealthiest of Americans. About half are obese and another 20% are overweight, they smoke much more than the general population and most of them don’t exercise regularly. On just about any index of health, they compare unfavourably to the general population. A lot of commercial drivers retire and die before the age of 60. I think by reducing fatigue, one of the benefits is improving the health and longevity of your drivers.”

There are two general categories of fatigue, Knipling explained. Acute fatigue refers to day-to-day drowsiness, which is primarily affected by the previous night’s sleep and the current day’s activities. Chronic fatigue, meanwhile, could be caused by a sleep disorder or long-term sleep deprivation.

Most humans require about eight hours of sleep per night and experience drowsiness between 2-7 a.m. and again in the afternoon.

Various studies have sought to determine how many crashes are caused by driver fatigue, but there has been no definitive conclusion. Knipling said studies have looked at whether fatigue caused the crash, and also whether it was present at the time of the crash, though not to blame. The most credible of those studies, he said, is the Large Truck Crash Causation Study, which found fatigue was present in 13% of truck crashes while it was to blame in 4% of all crashes. Another study by the National Traffic Safety Board examined fatal truck crashes in which the truck driver was killed, and determined 31% of those crashes were caused by fatigue. Knipling said the higher figure in that study was because fatigue is more likely to have been a factor in fatal truck crashes, where the truck often careens off the roadway.

There are two primary causes of fatigue: physiological factors (including the amount of sleep, time of day, how long the driver has been awake); and task-related factors (the type of work being done and how monotonous or complex the task is).

Another variable, said Knipling, is an individual’s susceptibility to fatigue in the first place. He highlighted studies that showed some individuals are affected by fatigue to a greater extent than others. In fact, one study showed that 14% of the drivers contributed 54% of the drowsy periods.

“Fourteen per cent of the drivers are more than half the problem,” said Knipling. “I’d say in your average fleet, that’s probably going to be the case. If you have a fleet of 100 drivers, a large part of your problem is those high-risk drivers. The challenge is knowing who they are, identifying them and helping them, or not hiring them to begin with, so that should be a big part of your focus.”

In yet another study, four subjects were monitored for lapses in attention while tired. Subject A had 14 times more lapses as Subject B.

“That’s not unusual,” Knipling said.

He also addressed hours-of-service, and opined that the current US rules are necessary and reasonable.

“My personal opinion is that they are reasonable rules,” he said. “If I were King, would I change them? No, I don’t think I’d change them much.”

That said, he admitted the rules themselves don’t effectively manage fatigue, because they don’t do anything to control the physiological factors of fatigue, such as quality of sleep or the time of day drivers can drive.

“They don’t address these individual differences in susceptibility,” he added. “Hours-of-service compliance is a good thing, but you can still have a lot of fatigue going on in a fully compliant fleet.”

The good news is that there are now more tools available to help educate fleet managers and drivers on the science of fatigue. The widely praised North American Fatigue Management Program is now available free-of-charge online at www.nafmp.com. Knipling was one of the developers of the program and would like to see it well used by industry. The program includes instructional modules designed for safety managers, drivers and even drivers’ families.

Among the information that’s revealed within the NAFMP are a list of dos and don’ts. Here are a few of them, as shared by Knipling during the Webinar:

Do: Value alertness and wellness; recognize sleep as a main ingredient; self-assess your fatigue level based on objective signs; try to go with, not against, your circadian rhythms; be aware of the fatigue factors affecting you at all times; seek sleep apnea testing if you have symptoms; and take breaks, especially with naps.

But don’t: Ignore signs of fatigue; use caffeine excessively; use alcohol as a sleep aid; eat heavy meals before driving; exercise strenuously just before sleep periods; let a sleep debt worsen; set the alarm clock on weekends; rotate your daily work-rest schedule backwards.