Visual effects of landscape decoration in the middle section of extra-long tunnel based on driving visual characteristics

To enhance driving safety and improve driving environment, an increasing number of extra-long tunnels incorporate natural landscape decorations in their middle sections. The influence of such decorations on the allocation of drivers’ attention resources remains unclear. Therefore, this study aimed to examine the visual effects of landscape decorations in the middle section of an extra-long tunnel. This study developed nine different landscape decoration scenarios based on a driving simulator. Eighteen male and twelve female drivers with at least three years of driving experience were recruited for the experiment. Each participant completed driving tasks under the nine landscape decoration scenarios, resulting in a total of 270 experimental trials (30 participants × 9 trials). To accurately capture the fixation shift characteristics of the drivers, the driver’s visual field was divided into six fixation areas using the mechanical partitioning method. The Markov chain model was then employed to predict the transition probabilities of fixation points and attention distribution characteristics, allowing for a comparison of the effects of different landscape decoration scenarios. Among the nine landscape decoration scenarios, the combination of ocean-themed sidewalls and gray road surface demonstrated the best performance, with drivers paying the least attention to the tunnel sidewalls. Furthermore, there is a significant difference in the drivers’ visual attention across different areas of interest. Under the same scenario, the drivers’ attention distribution across areas of interest (AOIs) was ranked from highest to lowest as follows: B (central close-range road surface) > A (central far-range field of view) > D1 (left sidewall) > D2 (right sidewall) > E (ceiling) > C (driver’s cabin). The Markov chain model proposed in this study effectively explored the impact of landscape decoration within long tunnels on drivers’ attention resource allocation. The findings highlighted the importance of considering the interaction of multiple landscape decoration factors when designing tunnel landscape sections. Specifically, the results demonstrated that a well-designed tunnel landscape decoration does not lead to excessive distraction of driver’s attention.