A virtual reality-based study on tunnel black hole effects on drivers' psychological stress and driving performance

The phenomenon known as the "black hole effect," which occurs at tunnel entrances, is a severe visual illusion induced by dramatic transitions in illuminance, space and reference. Previous studies on tunnel driving safety have been conducted mainly in real tunnels, making it difficult to isolate the effects of different tunnel lighting environments on driving safety and to accurately measure drivers' speed and distance estimations. Therefore, in this work, we introduce a virtual tunnel model with consistent lighting and introduce three scenarios: entering the tunnel (T1), outside the tunnel (T2), and open road (Base). We compared changes in ego speed and dynamic distance estimates for 30 drivers across the three scenarios using the time-to-contact (TTC) paradigm to investigate the effects of spatial transitions. Linear mixed model analyses revealed that spatial transitions caused drivers to significantly overestimate their own speed and underestimate the TTC and caused significant pupil dilation in the T1 scenario. However, results for T2 did not show significant differences in distance or speed estimation from the base results, but the pupil diameter increased significantly. The results of this experiment support the hypothesis that tunnels introduce spatial transitions that directly affect the ego speed and dynamic distance estimation and that tunnels induce driver stress immediately upon entry into the visual field.