Northwest Center Faculty Member Peter Johnson, PhD, MS focuses his research on ergonomics, bioengineering, whole body vibration,
computer-related disorders, and developing hardware and software technologies for
assessing exposures to physical risk factors. In his recent study he evaluated Whole Body Vibration (WBV) among truck drivers, and tested the effectiveness of interventions to reduce Whole Body Vibration and its adverse health effects.
Reducing Whole Body Vibration to Improve the Safety and
Health of Bus Drivers - NIOSH Science Blog Post
Posted on the NIOSH Science Blog October 12, 2016 by researchers Peter W. Johnson, PhD; Steven D. Hudock, PhD, CSP; Thomas McDowell, PhD; Elizabeth Dalsey, MA
On the road every day, transportation workers are
responsible for the safe delivery of passengers, materials and goods across the
United States. Bus drivers ensure our kids and family members arrive safely.
Bus drivers are vital to our economy, but their job can put them at increased
risk for health problems. In 2014, musculoskeletal disorders accounted for 23%
(n=3,400) of all injuries and illnesses resulting in days away from work for
bus drivers.
1
Bus drivers are vulnerable to health risks as their job
requires long hours sitting while absorbing vehicle vibrations from the roads
and highways. Whole body vibration occurs as a vehicle travels over roads and
the vibrations are transferred through the floor of the vehicle or seat into
the driver’s legs and spine. Vehicle design, type of driver seat including
suspension and seat cushions can affect exposure to whole body vibration. The
major impact of whole body vibration is the development of musculoskeletal
disorders, most commonly lower back pain, although upper extremity disorders
such aches and pains and weakness in the arm, shoulder, or the neck can occur
as well.2 Research has also shown that whole body vibration contributes to
other negative health effects including cardiovascular, gastrointestinal,
nervous and urological disorders.3 It is important to understand how to minimize
exposure to whole body vibration to reduce negative health effects on bus
drivers.
The Study
To address whole body vibration exposure, researchers set
out to determine the contribution of bus type on whole body vibration.
4 Two
different buses, a high-floor bus mainly used for longer commuter routes and a
low-floor bus often used as intercity buses with easy entry and exit for
passengers, were driven to compare whether performance differences
existed.
Both buses were driven on a
standardized route which included four road types to represent typical terrain
for bus drivers: newer smooth freeway, rough older freeway, city streets and
roads with speed bumps. Different drivers drove each bus with 12 professional
bus drivers operating the high-floor bus and 15 professional bus drivers
operating the low-floor bus. The buses used the same brand new, air-suspension
seat, and no passengers were onboard.
Whole body vibration exposures were evaluated using two international
standards, ISO 2631-1 (1997) and ISO 2631-5 (2004) to assess human exposure and
multiple shocks.
The Results
Researchers analyzed floor vibration and whole body
vibration exposure by road type. Whole body vibration differed significantly by
road type. In both buses whole body vibration exposure was greatest on roads
with speed bumps and lowest on smooth freeway. The high-floor bus had less
whole body vibration exposure on freeways and city streets but greater whole
body vibration exposure on roads with speed bumps. The brand new air-suspension
seat only reduced 10% of the floor vibration in both buses.
The Conclusion and Looking Ahead
Road type impacts whole body vibration in both the low-floor
and high-floor buses. Researchers recommend assigning buses to the appropriate
routes. On routes that contain speed bumps operate a low-floor bus.
Either bus would be appropriate on freeways
and city streets.
Research is underway to examine various seat suspension
technologies and their ability to minimize whole body vibration exposures to
professional vehicle operators. Similar to bus drivers, truck drivers are at
risk for exposure to whole body vibration. New active and air seat suspension
technology will be examined in trucks.
A fact sheet has been created summarizing Dr. Johnson's other research on reducing whole body vibration for truck drivers. Click
here to download.
________
Peter W. Johnson, PhD, MS, Professor at University of
Washington
Steven D. Hudock, PhD, CSP, Manager of the NIOSH
Musculoskeletal Health Cross-Sector
Thomas McDowell, PhD, Research Industrial Engineer in NIOSH
Health Effects Laboratory Division
Elizabeth Dalsey, MA, Health Communication Specialist in the
NIOSH Western States Division
References
1 U.S. Census Bureau for the U.S. Bureau of Labor Statistics
(BLS), Injuries, Illnesses and Fatalities: http://www.bls.gov/iif/
2 Lewis and Johnson P. (2012) Whole-body vibration exposure
in metropolitan bus drivers. Occupational Medicine, 62: 519 – 525
3 Okunribido, O., Magnusson, M., Pope, M.H., 2008. The role
of whole body vibration, posture and manual materials handling as risk factors
for low back pain in occupational drivers. Ergonomics 51 (3), 308-329.
4 Blood RP, Ploger JD, and Johnson PW. (2010) Whole body vibration exposures in forklift
drivers: a comparison of a mechanical and air-ride seat. Ergonomics, 53 (11):
1385 – 1394.
