Evaluation of the impact of landscape zone on driver distraction and visual comfort in road tunnels

Studies have shown that accidents in tunnels can be more severe than those in open road networks, and drivers are considered the critical factor for such accidents. An in-depth understanding of driver behavior helps analyze pre-accident safety measures and develop policies. Decoration of landscape zones is considered an effective measure for improving the driving environment inside road tunnels and has been widely adopted in China. However, the research on the impact of landscape zones on driving safety and comfort remains inadequate. It is worthwhile to explore whether the rich and colorful decoration of landscape zones results in driver distraction by excessively capturing driver’s attention, thereby increasing accident risk. To investigate this issue, a driving simulator was used, and tunnel interior scenarios characterized by three landscape zones with different spatial distributions (namely “wall,” “vault,” and “round”) were established. Eye tracking, driving performance, and pupil diameter data were collected to further analyze the driver’s psychological and physiological conditions while driving. The results showed that i) compared to no-landscape zones, the number of driver distractions increased when driving through landscape zones, with distractions caused by vault and round landscapes being particularly noticeable; ii) wall landscapes have certain advantage in maintain longitudinal driving speeds of vehicles more stable; iii) using normalized pupil diameter as an indicator for evaluating visual sensation, all three landscape zones can effectively improve the driver’s visual comfort, with no significant differences among the three; and iv) the pupil diameter changes of the wall landscapes were relatively stable compared to others, indicating the preference for landscape decoration on sidewalls inside the tunnels. The results of this investigation provide new insights into measures for improving the driving environment inside the road tunnels.