Högskolan i Skövde

VRDSs are useful tools in the road safety and driving behaviours research fields. Also, they are of great importance in the training and automation industry. However, drivers face various challenges challenges when they are driving in VRDSs, due to the differences between the real physical world and the virtual world. Speed perception is a determining factor in driving performance and response time and studies show that drivers were not able to accurately perceive speed of their vehicle in real-world and world-fixed VRDSs. There are numbers of studies on speed perception in fixed-worldVRDSs. Hence there seems to be a gap in this field and the accuracy of speed perception in HMD-based VRDS, and this filed is still an open field to explore, which this study tried to look into it.

The density of the environmental objects or in the other words the level of detail (LOD) of an environment influences the speed perception in VR. This study tries to investigate the effect of LOD on speed perception whether driving in a dense and sparse environment. The effect of the LOD on speed perception in HMD-based VRDSsystems is the second area which this thesis tried to conduct an experiment in this field.

In the narrow focus, the current study tries to first figure out if drivers faced challenges to accurately perceive their virtual vehicle speed in a developed HMD-base VRDS. Second, to find out in which environment, sparse or dense, they perceived their vehicle speed with higher quality. The experiment results show that the average driving speed for target speeds of 30 and 50 kph in the dense environment was better than the average driving speed for the same target speed in the sparse environment. In the other words, participants drove on average speed closer to the target speed in the dense environment. Furthermore, they expressed that driving at 30 kph sensed similar to driving a bike or running, which means the VRDS could not simulate the same experience as driving at slow speeds. Considering the average speed of participants, and their speed profile, the results show they perceived the 30 kph approximately as 10kph and 50 kph as 30. The analysis of the results, show significant difference betweent he speed that the VRDS tried to simulate and the speed the participants perceived visually.