BACKGROUND: Passive posture variation in vehicles could enable variation in pressure distribution and muscle activity to counter physical fatigue from static seating resulting in more comfort. The difference in posture, however, should not lead to perceived discomfort and aspects of driving should be considered such as operating the steering wheel, pedals and vision in the mirrors. OBJECTIVE: This study sets out to find out how much postural variation occurs during the driving task and how sensitive is the human body to these changes. METHODS: The first experiment was user evaluation and assessed how and when the changes in seat configuration were noticeable to the human body. The second experiment evaluated the influence of varying inclination of the backrest and the seat pan by the rating of typical aspects of driving. RESULTS: The differences in seat configuration during experiment 1, were so small that there was no consistency in the ratings for the same configuration. The most critical feature that restrains the posture is the location of the rear view mirror. CONCLUSIONS: The range-of-motion is defined as -1° to 1°for the seat pan and 0°to 1.5°for the backrest based on the results of experiment 2 because of the restraints of the driving task.@en

This thesis aims to decrease the feeling of tiredness related to an on-going monotonous, undemanding driving task. It is not intended to enable people to drive longer, but rather for them to experience the time they spend driving as more pleasant. The perception of fatigue is considered as a type of discomfort. From this follows the hypothesis that this feeling of tiredness develops according to a similar system as the perception of discomfort or comfort. Following this premise, the approach in this thesis is to alter the interaction with the vehicle interior by developing features resulting in certain bodily sensations that contribute to feeling more fit.@en

Most research on product comfort focuses exclusively on the use of the evaluated product (e.g., Kyung, Nussbaum, & Babski-Reeves, 2008; Harih & Dolšak (2013). We sought to investigate the influence of a sitting precondition on ratings for first impression of comfort, short-term comfort, and discomfort of a product. The aim was to assess if and how sensations experienced prior to product use affected product evaluation. Therefore, a vehicle seat was evaluated with two preconditions in a withinsubjects design. The comfort model of Vink and Hallbeck was extended according to the findings of this study.@en