M.Y. Rosnaha et al. AJE Vol.9 2009 1-17
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in a risk score between one and seven, where higher scores signify greater levels of apparent risk. RULA analysis examines the following risk factors: number of
movements, static muscle work, force, working posture, and time worked without a break. RULA evaluates stress on each body part; the level of severity suggests which
features of the chair should be modified to make it more comfortable.
2.4.2. Current seat measurement
Several measurements were taken on the current seat Figure 3.
3. Results
3.1. Sampling and Observation
The seats in the three buses sampled, none had armrests, headrests or seatbelts. Armrests support the arms and prevent or reduce arm, shoulder, and neck fatigue.
The headrest supports the weight of the head to reduce amount of stress on the body. Therefore adding armrests and a headrest should reduce fatigue among bus
drivers. However, the lack of a seat belt simply showed a disregard for safety.
3.2. Body part Symptom survey
The respondents for this study were mostly 12 31-40 years old and had worked as bus drivers for an average of 5-7 years. Of the 25 respondents, 18
indicated that they experience some musculoskeletal problems and 16 of these indicated that these problems first occurred after they had become drivers. In 23 of
the workers, the most frequent problems were in the lower back, followed by pain in the neck or head 21, in the ankle or leg 20, in the thigh 17 and in the arm or
hand 15. This result is consistent with that of the larger survey. Based on interviews and chair design observation, possible causes of the prevalent problems
were identified Table 1.
3.4. Current Seat measurement
The measurements the current seat Table 3 will be compared with the relevant anthropometric data to recommend a new seat design.
Development and Evaluation of Bus Seat Dimension to Improve the Fit and Comfort of Malaysian Bus Drivers
7
Figure 3.
Seat dimensions measured. a. seat pan height, b. seat width, c. seat depth, d. backrest height, e. backrest width and g.
lumbar support height, f. angle of inclination. Table 1.
Summary of complaints and possible causes
Driver Complaints Observation of Seat Used
Lower back Absent or improper
lumbar support Neckhead No
headrest AnkleLeg Inadequate
support; Inadequate leg room
Thigh Seat height is not
adjustable Armhand No
armrest
Table 2. Mean and standard deviation anthropometric.
Dimension Mean
SD
Stature 164.63 5.57
Weight 72.31
11.88 Eye height
115.28 4.57
Shoulder height 98.54
4.06 Elbow-rest-height 64.37
3.31 Knee height with shoes
52.79 3.06
Knee height without shoes 50.15
2.48 Popliteal height with shoes
43.06 2.53
Popliteal height wo shoes 40.88
2.27 Elbow breadth
47.03 5.06
Hip breadth 35.23
4.11 Buttock-to-popliteal depth
43.47 3.04
Buttock-to-knee depth 54.10
3.37 Lumbar support height
42.50 9.16
Note: N=25, Units are in centimeters except for weight kg.
