19 | Methodological comparison of a trajectory-controlled test-track study to naturalistic on-road study on carsickness and influencing factors

To investigate the causes of carsickness, manufacturers and research institutes conduct experiments on test tracks or in simulators, as automated vehicles are rarely available for studies. Manual driving on public roads is an alternative, but variations in driving dynamics complicate comparisons. This study examines carsickness during manual driving on public roads and under comparable conditions on a test track and the impact of non-driving-related tasks, emotional factors, and performance deviations.The sample consisted of 47 participants. A vehicle was manually driven along a fixed route or automatically controlled based on a trajectory on a test-track. The experiment followed a within-subject design for testing environment, NDRT and performance.The repeated measures ANOVA with time and test environment showed that there was a significant effect of time but no effect of environment based on the MISC scores. The trajectory was optimized to replicate lateral accelerations while compromising longitudinal accelerations due to the boundaries of the test-track. Most interestingly, the differences in the stimuli are not confirmed by the resulting MISC ratings. Meanwhile, most of the psychological factors do not differ between road and test-track, suggesting that both environments are comparable in this respect. The variation of NDRTs (administered to investigate optical flow in videos), and measures of cognitive performance were not related to the occurrence of carsickness. The methodology has shown to be efficient in reproducing carsickness exposure and allowing comparison between test-track and on-road for motion sickness experiments. This method enables efficient experimentation for modeling carsickness and developing countermeasures.