Do drivers' gaze behaviors differ between special road sections of mountainous expressways? A comparative study of...

This study aimed to examine differences in drivers' visual information acquisition between long downhill and tunnel sections of mountainous expressways, providing evidence for traffic safety interventions in special road sections.

A naturalistic on-road eye-tracking experiment was conducted with 27 drivers, and eye-tracking data were collected under two road scenarios. Based on the area of interest (AOI) division, this study used fixation frequency, percentage of fixation duration, mean fixation duration, mean saccade velocity, and pupil area to analyze drivers' visual attention allocation, visual search rhythm, and visual adaptation demand. A linear mixed-effects model was further used to identify the effects of road scenario and AOI type.

In the long downhill section, drivers' visual attention was mainly concentrated on the left lane, right lane, and right-side signs and right mirror. In the tunnel section, drivers showed increased attention to the dashboard and forward lanes, whereas their attention to lateral information decreased. Compared with the long downhill section, the tunnel section showed lower mean saccade velocity and larger pupil area values, suggesting more concentrated visual search and stronger light-dark adaptation demand under tunnel lighting-transition conditions.

Long downhill and tunnel sections corresponded to different visual task patterns. In the long downhill section, drivers relied more on coordinated monitoring of the forward roadway and right-side information, whereas in the tunnel section, they showed a stronger forward-concentration tendency and stronger light-dark adaptation demand. These findings may provide a preliminary reference for scenario-sensitive visual-environment optimization in special road sections. For long downhill sections, continuous guidance and speed-limit information may be considered, whereas for tunnel sections, attention may be given to portal visual transition, lighting transition, and in-tunnel information organization.