Thomas Louwers

Project title: Analysis of an Intervention to Reduce Truck Drivers' Exposure to Whole Body Vibration

Degree: MPH | Program: Occupational and Environmental Medicine (OEM) | Project type: Thesis/Dissertation
Completed in: 2016 | Faculty advisor: Peter W. Johnson


Analysis of an Intervention to Reduce 
Truck Drivers’ Exposure to Whole-Body Vibration 

Louwers, TD1,2; Johnson, PW1; Davies HW3; Martin, GJ2; Vedal, S1; Wang, F4; Du, B5; Hughes, M1 

1Department of Environmental and Occupational Health Sciences, University of Washington 
2Department of Occupational and Environmental Medicine, Madigan Army Medical Center 
3School of Population & Public Health, University of British Columbia 
4Department of Industrial and Systems Engineering, University of Washington 
5School of Public Health and Health Systems, University of Waterloo 

Introduction. The high prevalence of low back pain in drivers of commercial motor vehicles is well-documented. A number of interventions have focused upon the factors of support of the lumbar region of the spine, sedentary work, long hours, and exposure to whole-body vibration (WBV). 

Objective. An intervention to be evaluated is an air-filled ballistic seat pad designed to reduce exposure to WBV. The effectiveness of the seat pad in motor vehicles has not yet been established. Results from a previous pilot study involving 12-ton and 16-ton vibratory rollers used by Seattle Public Utility drivers suggest that the seat pad is not effective at very low speeds (1-3 mph). 

Methods. The current study compares WBV exposures in nine truck drivers at their existing air-suspension seat and at the seat pad which sits on top of their seat. This study uses a Wilcoxon signed rank test to compare the seat pad’s effectiveness in reducing WBV exposures relative to their existing air-suspension seat. 

Results. Overall, the truck drivers' vibration exposures were above daily vibration action limits and the air-filled ballistic seat pad did not significantly reduce WBV exposure. 

Conclusions. The question of whether the air-filled ballistic seat pad may significantly reduce the incidence, prevalence, or severity of low back pain in drivers of commercial motor vehicles remains, particularly with respect to varying road types and driving conditions. The answer may lie in a future analysis of the power spectral densities. Buses produce more high frequency energy, where the air-filled seat pad was shown to be effective. Trucks produce less high frequency energy, which may diminish the air-filled seat pad’s effectiveness.