10.2025 - Article

This study focuses on the ergonomics of bus drivers’ workstations, i.e. the bus cab.

In a previous study, we found that the most common problems among bus drivers are musculoskeletal disorders, such as shoulder and back pain. In the international literature, these conditions are often linked to workplace ergonomics. As we had no data on bus ergonomics in Switzerland, we carried out measurements on buses.

Some studies do exist, but they are mainly based on human subjects — as is typically the case in ergonomics — which means that the results cannot be directly compared or generalised to other contexts. These studies generally focus on a small number of participants, most often exclusively men, and rarely provide detailed information about the buses used. Our approach thus differs from conventional ergonomics, which places the human at the centre and relies on a high degree of personalisation.

The first objective is to develop ergonomic scores based on different parts of the body. The second objective is to extend the ergonomic scores obtained for a limited number of buses to the entire Swiss bus fleet.

Drawing on the scientific literature and in collaboration with ergonomists from Unisanté, we have created a checklist of parameters to be measured (e.g. the size of the windscreen, the height of the headrest, the length of the seat, the contrast of the dashboard icons, etc.) inside the bus cabin. These parameters are then converted into yes/no variables (compliance with recommendations/non-compliance with recommendations). Scores, broken down by body part (overall, visual, shoulders, upper body, back, lower body), are calculated by averaging the yes (=1) and no (=0) variables, weighted according to risk and frequency. Scores range from 0 to 100, with 100 corresponding to more ergonomic and comfortable vehicles. The ergonomic scores are measured in 10 buses and then extrapolated to the entire Swiss bus fleet. This produces the bus-ergonomics matrix. To track changes in ergonomic scores in Switzerland, the bus-ergonomics matrix is cro

The bus ergonomics matrix contains 705 buses and includes overall (all), visual, shoulders, upper body, back and lower body scores. All ergonomics scores improved between 1970 and 2025. The smallest improvement was in the lower body score, which rose from 44 in 1970 to in 2025. The greatest increase is seen in the upper body score, which rises from 11 in 1970 to 90 in 2025. In 2025, the overall, biomechanical, shoulder, upper body and back scores are above 80, whilst the visual and lower body scores are 69 and 70 respectively.

All the scores have improved, which should make the buses more comfortable and ergonomic. This is true provided the driver has time to adjust their seat before setting off.

One of the study’s strengths is the creation of a score based on objective parameters. This enables a comparison between buses. Another strength is the collaboration with ergonomists from Unisanté, who provided valuable expertise. The final major strength of this study is the use of advanced statistics to model the scores for all buses in the inventory. This method, known as the Integrated Nested Laplace Approximation (INLA), utilises mathematical shortcuts in simulation methods and enables data to be analysed quickly and reliably in complex situations. In practical terms, this provides a better understanding of the links between bus characteristics and ergonomic scores, whilst saving significant computation time and maintaining accurate results. One limitation of the study is that the entire modelling of ergonomic scores is based on just 10 buses. A larger number of buses would have yielded more accurate results.

This study enables the creation of an assessment tool based on the buses driven. It will be possible to establish ergonomics scores using questionnaires that include a record of the buses driven throughout a driver’s career.

This bus ergonomics matrix will enable us to investigate the link between the working environment and various health issues, such as musculoskeletal pain, among bus drivers. This tool will be used in future studies.