Reducing Whole Body Vibration to Improve the Safety and Health of Bus Drivers

Posted on by Peter W. Johnson, PhD, MS; Stephen D. Hudock, PhD, CSP; Thomas McDowell, PhD; and 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.

NIOSH wants to hear from you!

What are the challenges to mapping new routes to avoid rough roads?


Peter W. Johnson, PhD, MS, Professor at University of Washington

Stephen 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



1 U.S. Census Bureau for the U.S. Bureau of Labor Statistics (BLS), Injuries, Illnesses and Fatalities:

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.

Posted on by Peter W. Johnson, PhD, MS; Stephen D. Hudock, PhD, CSP; Thomas McDowell, PhD; and Elizabeth Dalsey, MA.

12 comments on “Reducing Whole Body Vibration to Improve the Safety and Health of Bus Drivers”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    Whole body vibration can cause bursitis as well. I think you should also inquire as to who is suffering from bursitis of the hips. Last, if you could offer some suggestions on how to lower the chances of whole body vibration would be great.

    Back in 2007 my back was injured due to pothole. Already had some problems but mainly ok. Ten years later I’m disabled, can’t work or do anything for more than couple hours. Stenosis, buldging disks, nerve damage. L2-3-4-5 S1. Migraine, dizziness in and out all day night long, trouble sleeping and common chores. Major Depression, angizty, social problems. Workers comp., SSD now with medical coverage. God Bless, Peace

    It’s too bad you don’t do ANY research for things that will actually work today. Actually having a workable, doable, and easy approach to these things should be an embarrassment to you. Obviously, it’s not. It’s also obvious that you want to continue research in bull**** bogus ideas that should ahve been taken care of in the seventies. This is all old, old crap. I’ve watched you and your “team” do this less than useable information for all these decades of mostly unusable clap trap. But do keep doing it as it employs people. Just don’t think you can fool everybody. The insidious, bogus, research you do should be an embarrassment to your entire CDC network. please do come out into the REAL world and see things that actually have worked for 30 years. And you young researchers, go somewhere where you can actually get real research done that can help actual real people without the bull**** embarrassingly, oblique, wasted money you are currently involved in. I am responsible for my comments, I mean them and I seriously doubt this will be posted, but only because of the peanut brains running your organization. [asterisks added by NIOSH]


    Richard Rossiter

    I don’t normally comment on CDC blogs, but bro. Your education is in geology and history (3 years). Let the people who have been studying this for years continue doing so; it is difficult research because it is such a prevalent problem and therefore hard to nail down to any particular set of contributing factors. Hop off please.

    Yes, there are established exposure limits for whole-body vibration (WBV). The International Organization for Standardization (ISO) has published ISO standard 2631-1 (2010) that provides a methodology on the measurement, evaluation, and assessment of WBV exposures for health risks, discomfort, and performance. While this standard defines the parameters to be measured and evaluated, it does not give specific limits for each parameter; it is up to each country to specify WBV exposure limits. Many countries have established such limits based on ISO 2631-1 guidelines. For example, in the European Union, the Commission of the European Communities Directive 2002/44/EC is based on the ISO standard guidelines and provides statutory provisions governing workplaces for the protection of workers against vibration. The Directive establishes daily action values and limit values for exposures to WBV. In the U.S., the American Conference of Governmental Industrial Hygienists (ACGIH) has issued Threshold Limit Value (TLV®) and Action Level (AL) curves based on the Health Guidance Caution Zones defined in ISO 2631-1. The American National Standards Institute (ANSI) has also adopted the ISO 2631-1 standard as a nationally adopted international standard ANSI/ASA S2.72. We recommend that you refer to current ACGIH and ANSI documentation for proper application of the exposure limits and action values for limiting WBV health risks. The U.S. military standard MIL-STD 1472G also uses ISO 2631-1 for establishing recommendations and limits for WBV exposures. Neither the U.S. National Institute for Occupational Safety and Health (NIOSH) nor the U.S. Occupational Safety and Health Administration (OSHA) has issued or adopted WBV exposure limits.

    I think you should also inquire as to who is suffering from bursitis of the hips. Last, if you could offer some suggestions on how to lower the chances of whole body vibration would be great.

    I like what you have found in this study. However, I am interested to know if a similar study was or will be conducted for rail operators and how the ergonomic seating impacts the operator’s health.

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