Neural oscillations underlying the impact of the road environment on hazard perception

The driving environment shapes hazard perception, but the underlying neurocognitive mechanisms are not fully understood. This study used electroencephalography (EEG) to investigate how road types influence hazard perception in 36 drivers using a 2 (urban street vs. expressway) × 2 (hazard-present vs. hazard-absent) design. Analysis of intra-individual variability (ICV) revealed no significant differences in cognitive control stability between expressway and urban street conditions; however, expressway driving was associated with shorter reaction times and higher error rates. Although the influence of parallel mechanisms, such as reduced vigilance or attentional disengagement, cannot be entirely ruled out, this pattern is consistent with a shift in cognitive processing toward a less effortful, automated mode, suggesting that expressway environments may trigger a specific adaptive mechanism. At the neural level, hazard stimuli on expressways were accompanied by more pronounced parietal α oscillations and relatively weaker functional connectivity between frontal and parietal electrode sites in the β_H band. This may reflect a neural state inertia in expressway environments, which hinders the flexible reallocation of cognitive resources when perceptual and attentional demands increase during hazardous situations. To quantify the difficulty of rapidly switching from automated to controlled processing, this study introduces a β_H-α composite index for an exploratory characterization of this cognitive bias. Based on these findings, practical implications are provided for road environment design, in-vehicle or roadside warning systems, and driver state monitoring technologies.