Melina Makris, Design & Human Factors

While previous car comfort research has predominantly focused on physical discomfort and on drivers, empirical knowledge of passengers’ perceptions of ride comfort remains limited. This thesis addresses this gap by adopting a holistic, passenger-centred perspective on ride comfort in cars. The overall aim of this thesis is to increase the understanding of car passengers’ perceptions of ride comfort, grounded in passengers’ own experiences. To achieve this aim, a mixed-methods research approach was employed, across four empirical studies described in five appended papers. The research progressed iteratively, beginning with a focus on physical comfort, posture, and seat belt fit, and gradually expanding to include psychological comfort, functional comfort and activity engagement. The data collection methods included interviews, questionnaires and video observations from in-car studies on road, as well as free-text responses from a survey of a broader passenger population, enabling exploration of passengers’ own perceptions of ride comfort.
 
The findings show that passenger ride comfort constitutes three interrelated dimensions: physical, psychological, and functional comfort, influenced by a combination of individual, artefactual, and contextual factors. These dimensions interact dynamically over time, such that changes in one dimension may trigger or amplify changes in others. Psychological comfort, particularly related to perceived safety and control, emerged as foundational for passenger ride comfort, while functional comfort, defined as the possibility to engage in activities, played a central role in how passengers regulate both physical and psychological comfort. Based on these findings, the thesis presents a holistic Passenger Ride Comfort Framework, illustrating relationships between passengers’ perceptions of ride comfort and influencing factors, and provides empirically informed questionnaire tools for assessing passenger ride comfort. These contributions can support future research as well as evaluation and development of interiors in new passenger cars.
 
In conclusion, passenger ride comfort is a complex phenomenon that extends beyond physical factors to include psychological aspects, activity engagement, and contextual influences during a ride. Passengers’ perceptions of ride comfort are continuously reassessed over the course of a ride in response to activities, focus of attention, and dynamic influencing factors, rather than reflecting a sum of isolated factors. Capturing this complexity requires empirically grounded mixed-methods approaches, in which objective and subjective measures are combined to provide a complementary basis for analysis, while interviews and free-text responses support the interpretation of questionnaires and video observations, advancing the understanding of passengers’ perceptions of ride comfort.