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Wednesday, May 29, 2024

Vibrations cause pain

Any trucker who’s steered a rig down a rough road knows you can feel the same bump twice — once when you hit it and again the next morning when you get out of bed.

Aches and pains from being bounced around in the cab 10 to 11 hours a day have been as much a part of trucking as heartburn from truck stop food, but evidence is growing that the vibration truckers experience behind the wheel can cause drivers pain and might even affect their performance.

“Whole body vibration” is the term researchers use for the motion caused by a truck traveling over a rough surface, vibration transmitted up from the road through the seat to the driver. It can cause sore lower backs, as well as pain in the neck, arms and legs. If the pain is bad enough, it can limit or cut short a driver’s career.

A sore back and legs have long been considered occupational hazards of driving a truck, but new research indicates WBV can also hurt drivers’ performance behind the wheel. A definitive large-sample, long-range study has not been completed, but studies done with limited samples indicate that vibration is a problem for truck drivers.

A study presented at the 2014 American Conference on Human Vibration examined how WBV affected drivers’ performance on tests after exposure. In a lab, eight truckers were exposed for two hours apiece to two levels of WBV, one of the type experienced in a passive suspension seat and the other at the level experienced in the Bose Ride® active suspension seating system. The Bose Ride uses sensors and electromagnetic motors to greatly reduce WBV.

Afterward, the subjects performed computer-based tests that measured their reaction time to stimuli. Compared to those in the active-suspension seat, drivers using the passive-suspension seat had slower response times and more lapses per trial.

“Therefore,” the limited study concluded, “it appears WBV exposures and the magnitude of the WBV exposures may adversely affect the vigilance of truck drivers and potentially contribute to cognitive fatigue.”

In addition to slowing reaction time, WBV could make drivers tired and sleepy. A 2015 RAND Corp. review of 24 studies examining WBV and fatigue and sleepiness found that 18 of the studies reported “a significant association” between WBV and driver fatigue and sleepiness, while the others found no relationship.

The review concluded that reducing WBV among truck drivers “may reduce fatigue and ultimately reduce the public-health burden and societal costs of trucking accidents.” The report, which was commissioned by Bose and insurance giant AIG, concludes that further study is needed to establish a causal relationship.

Looking for a way to reduce WBV-related pain, the Washington State Department of Labor & Industries commissioned a study to investigate whether active suspension seats could reduce WBV and back pain.

The double-blind, randomized field study compared the Bose Ride system and the industry standard air-ride seat. Measurements showed that truck drivers who used Bose Ride experienced less WBV than those with air-ride seats. After three months, the Bose Ride group reported a 30 percent reduction in lower back pain, compared to a 10 percent reduction with those who received new air-ride seats and a 2 percent increase with those who kept their existing air-ride seats.

A limited 2015 study published in the Journal of Occupational and Environmental Hygiene found that seats with active suspension systems, like the Bose Ride system, transmit significantly less vibration than do standard air-suspension seats.

A number of carriers are retrofitting their fleets with Bose Ride systems for the benefit of their drivers. R+L Carriers of Wilmington, Ohio, has installed Bose Ride systems in the majority of its 4,000-truck fleet.

“The feedback has been great,” said R+L CEO Roby Roberts. “We hear that people feel better at the end of each workday. Their body feels better with less fatigue and they feel they can do more.”