Test-track and On-road studies: Methodological Insights on the Assessment of Carsickness and its Modulating Factors

The research on motion sickness and the work on effective countermeasures has gained additional attention due to the ongoing development of highly automated driving vehicles. In order to understand the phenomenon of motion sickness better and support the testing, this work sheds lights on motion sickness and multiple factors connected to it: The relation between the development of carsickness and testing environment itself is explored as well as their connection to psychological factor. Simultaneously, carsickness is often stimulated by non-driving-related tasks (NDRTs), while publications have shown different effects on motion sickness by various NDRTs. Therefore, it is also investigated whether the optical flow influences carsickness. Lastly, it will also be investigated whether there is an effect on performance caused by carsickness across different testing environments. 47 participants participated in an within- study in a vehicle either driving on a public road or on a test track. While administering comparable accelerations and two randomly assigned NDRTs, carsickness, psychological factors and performance was measured within these environments. The results indicate that it was possible to set-up rides in both environments which led to comparable motion sickness stimuli based on the vehicle accelerations. The optical flow did not lead to different carsickness. At the same time, few differences could be found among psychological factors, although they do not indicate that the transfer of results between testing environments would not be valid. Lastly, cognitive performance was affected by the two testing environments with regard to the reaction time. This work elucidates on the one hand that multiple factors influence motion sickness, though much remains, yet, to be understood. On the other hand, the feasibility of conducting comparable studies in different testing environments is shown. If the transfer of such is fully realized, motion sickness research can proceed in an effective and intertwined way.