Measuring discomfort towardthe car seat is important as the act of driving requires a driver to remain at the car seat while controlling the car. The seat condition, including sitting position as well as the driver’s posture can lead to discomfort and fatigue. The objective of this study is to investigate a driver’s pressure distribution in static and dynamic circumstances for two types of cars; the sedan and compact car. This study involved both subjective and objective evaluations of 12 respondents. For the subjective evaluation, the Visual Analog Scales (VAS) were used to obtain respondents' perception of discomfort. For the objective evaluation, pressure distribution readings of the seat interface were obtained using piezo capacitive sensors. The findings showed that the highest pressure was recorded for the compact car. Furthermore, the static circumstance showed greater pressure compared to the dynamic state. Subjective evaluation indicated that the right buttocks and the lower back (lumbar)experience the highest discomfort for both types of seats.The type of seat found to contribute to the value of different pressure. Thus, it can be concluded that appropriate seat selection can reduce pressure as well as discomfort.
Pressure ; car seat ; back rest ; static ; dynamic ; sedan ; compact

Discomfort and pain issue at the body part are common complaints reported by car drivers. It is due to driving task require physical demands and need to maintain and adapt several postures in a constrained space while controlling the car. Hence, this study aims to determine the pattern of shoulder activation muscle consisting of the Trapezius muscle in two different driving posture. Respondents were required to grasp the steering wheel at 8 and 4 hand position. The Surface Electromyography was used to get the reading for left muscle’s Trapezius Descendent (TD) at two different positions; i) closest distant from steering wheel and ii) far distant from the steering wheel. Then, Temporal Analysis was used to evaluate the pattern of the driving action. From the experiment, it shows the different value of muscle activation occurred while driving according to turning action. The far seated position depicted greater activation on driving action compared to the closer seated to the steering wheel. In conclusion, the driving posture effects the activation of shoulder and arm’s muscles as early as after 20 seconds of driving activity. Hence, choosing the correct driving posture allowed a comfortable driving environment for the driver.
Trapezius ; steering wheel ; SEMG ; driver ; temporal analysis ; driving posture

Proper driving requires a proper posture to bring comfort to drivers. A problem that commonly exists in driving is incorrect driving posture which can cause discomfort to the driver, especially when interacting with automotive pedals. Research on contraction of tibialis anterior (TA) muscle on driver's posture based on the knee angle less than 101º in a position of pressing and releasing a pedal was conducted to investigate and overcome this problem. This is a field experiment study and surface electromyography (sEMG) is used in collecting data on the TA muscle. The procedure of collecting data on the TA muscle before and after experiments follows the Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles (SENIAM) recommendations. The result of the experiment shows that there is a strong negative relationship between driver's postures in nature based on the angle of the knee with TA muscle contractions, where the Pearson correlation coefficient (r) is - .993. While the temporal analysis measurements based on Maximum Voluntary Isometric Contraction (MVIC) 60% in a position of releasing a pedal exceeding rms µV 39.38, are 39.71 and 40.25 respectively. On the other hand, MVIC 2% rms µV values: 1.19 and 1.2 are obtained in the position of pressing the pedal. The knee angle with TA muscle contractions is significant [F (1, 10) = 660, p<.05] contributing 98.5% variance (R2 = .985) in the driver's posture. A linear equations model has been developed to clearly illustrate the result. In conclusion, when the knee angle of the driver's posture is increased, the TA muscle contraction is decreased. The increase in the knee angle will directly provide comfort to the driver while interacting with the pedal; and this is due to the reduction of TA muscle contractions.

While driving, a driver is required to control the steering wheel to change direction. The driver’s muscles of the upper limbs and shoulders are involved in such a task. Therefore, an assessment of the driver’s physiology according to certain condition is necessary to improve driving comfort and safety. This study aims to investigate the driver’s Deltoid Anterior (DA) muscle activity while operating the steering wheel. Eleven test subjects were recruited for an experiment using a car simulator. They were required to remain in the car seat and perform the task of steering the wheel. Surface electromyography (SEMG) was used to record each subject’s muscle contraction while turning the steering wheel to the right and left by several degrees. According to the findings, 45 degrees turning recorded the highest Root mean Square (RMS) value for DA. In addition, DA muscle activation increased with more degrees turning.
Deltoid anterior ; steering wheel ; SEMG ; driver ; discomfort ; distant seated posture