This field study evaluated a newer and older dozer at a construction site. Both dozers performed similar activities in the same location within the construction site. Two operators participated in this study. One operator used the older equipment and the other operator used the newer equipment.

Jolting and jarring measurements were taken at the seat/operator interface and at the floor of the cab. The result of this field study indicates that the newer dozer was better than the older dozer.


Work related injuries and illnesses pose a continuing threat to the health and well-being of American workers. The construction industry has been historically recognized as having higher rates of fatality, injury, and illness than other industries (McVittie, 1995; BLS, 1996). In 1994, there were an estimated 218,800 lost workday injuries in the construction industry (BLS, 1996). Construction also had the second highest incidence rate for sprains and strains. Operating engineers (also known as hoisting and portable engineers) operate and maintain the heavy construction equipment, such as cranes, bulldozers, front-end loaders, rollers, backhoes, and graders. They may also work as surveyors or mechanics. The operators use these equipment to perform four main tasks (Stern and Haring-Sweeney, 1997): 1) the building of roads, bridges, tunnels, and dams; 2) the construction of buildings and power plants; 3) the removal of earth materials and grading earth surfaces and in the replacement of concrete, blacktop, and other paving materials; and 4) the constructing of drainage systems, pipelines, and other related tasks, such as blasting. It is estimated that there are 487,000 operating engineers (55% union and 45% non-union) in the United States and Canada. The majority of these workers are exposed to whole body vibration, albeit in concert with other occupational risk factors.

Past studies have shown that musculoskeletal disease affecting operators of construction equipment appears to be due to awkward postures (including static sitting), whole body vibration, work intensity, high resistance levers and repetitive motions (Kittusamy and Buchholz 2001; Kittusamy, 2002; Buchholz et al., 1997). It is believed that reducing ergonomic exposures, such as whole body vibration and postural stress, may be an important factor in improving the health, comfort and efficiency of these operators.