Härtill 2 uppsatser

Licentiatavhandling. (sammanfattning) Göteborg : Chalmers tekniska högskola, 2023

This licentiate focused on examining the effectiveness of short stationary studies versus long driving studies in evaluating sitting postures, belt fit, and sitting comfort in cars. The study employed a mixed-methods approach, in which 19 participants experienced two different test scenarios in the rear seat of a car: a stationary scenario in an indoor garage and a driven scenario on a predefined route in regular traffic, each lasting 45 minutes. The data collection methods captured objective and subjective data through video recordings, questionnaires, and interviews. The Wilcoxon’s signed-rank test was used to identify significant differences in sitting postures and seat belt positions estimated by a machine-learning based algorithm, as well as differences in discomfort ratings between the scenarios and over time, while interviews were analysed thematically. The findings revealed that shorter, stationary studies of three minutes effectively captured the average sitting postures and belt fit, while more extended studies were necessary to capture posture variations. The results emphasized the importance of longer driving studies for comprehensively assessing variations in shoulder belt positions, particularly for individuals with specific body shapes. Additionally, the study emphasized the influence of the type of study scenario and duration on the comfort experience. Discomfort changes became noticeable after 15 minutes in both scenarios. Particularly, discomfort increased over time in the back, buttocks, thighs, and feet. Increased back discomfort was associated with participants adopting slumped postures. Furthermore, the type of scenario influenced the participants' emotions and behaviours, with the stationary scenario leading to increased awareness, boredom, and tiredness due to the lack of visual and haptic stimuli. In contrast, the driven scenario resulted in more natural movements and engagement in window-gazing. Lastly, the study highlighted the complex relationship between posture data and discomfort perception.