Ergonomics assessment of locally fabricated passenger seats in trotro vehicles in Accra, Ghana

Trotro vehicles constitute one of the major means of transportation in Ghana by way of ferrying people and goods. Most trotros are originally brought into the country as load carrying vehicles, which are then converted into passenger vehicles. Locally designed seats are then fabricated and secured into the vehicles. The study explored the ergonomic evaluation of the locally fabricated passenger seats with anthropometric measures of passengers and also compared the seat dimensions to required standards. The study was undertaken at seven selected bus stations in Accra, the capital city of Ghana. The study composed of 307 volunteer passengers comprising 175 females and 132 males with ages spanning from 18 to 60 years. The dimensions of ninety locally fabricated seats were collected from ninety randomly selected trotro vehicles. Ergonomic assessment was performed to determine match or mismatch between the anthropometric measures and vehicle seating dimensions. In addition, the fabricated seat dimensions were compared to both local and international vehicle seat standards. High mismatches indicating that the passenger seats were probably too deep or too high were observed for seat height – popliteal height, seat depth – buttock popliteal length, and seat breadth – hip breadth. A low mismatch was observed between the sitting height and backrest height for 99.4% of participants. Only four and ten out of the ninety seats complied with specified standard seat length and backrest to backrest distance, respectively. The high prevalence of mismatch is a possible indication that most locally fabricated seats do not adequately accommodate majority of passengers. Furthermore, it appears that anthropometric measures and standard vehicle seat dimensions are not considered during seat design, with potential health ramifications pertaining to the safety, comfort and sitting posture of passengers.