Perception of driving simulations: Can the Level of Detail of virtual scenarios affect the drivers behavior and emotions

Human factors studies are becoming more and more crucial in the automotive sector due to the need to evaluate the drivers reactions to the increasingly sophisticated driving assistant technologies. Driving simulators allow performing this kind of study in a controlled and safe environment. However, the driving simulation's Level of Detail (LOD) can affect the users perception of driving scenarios and make an experimental campaigns outcomes unreliable. This paper proposes a study investigating possible correlations between drivers behaviors and emotions, and simulated driving scenarios. Four scenarios replicating the same real area were built with four LODs from LOD0 (only the road is drawn) to LOD3 (all buildings with real textures for facades and roofs are inserted together with items visible from the road). 32 participants drove in all the four scenarios on a fixed-base driving simulator; their performance relating to the vehicle control (i.e. speed, trajectory, brake and gas pedal use, and steering wheel), their physiological data (electrodermal activity, and eye movements), their subjective perceptions, opinions and emotional state (questionnaires concerning the research and Self-Assessment Manikin Scale) were measured. The results showed that drivers behavior changes in a very complex way. Geometrical features of the route and environmental elements constrain much more driving behavior than LOD does, as observed for vehicle trajectory and speed; skin conductance and gas pedal appear to be more sensitive to LODs. Gaze position changes according to LODs, but differently for rectilinear and curvilinear segments. Pupil diameter increases with higher LODs. Emotions are not affected by LODs. Generally, different signals showed different correlations with the LOD level, suggesting that future studies should consider their measures while modeling the virtual scenario. It is hypothesized that scenario realism is more relevant during leisurely environmental interaction, whilst simulator fidelity is crucial in task-driven interactions.