## 1 Introduction  
Highway tunnels are now widely used in China for their ability to overcome adverse terrain and other advantages [1]. Among those advantages are various characteristics of urban tunnels: the driving speed is relatively slow, and it takes a long time for vehicles to pass through the urban tunnel body part, which may even easily lead to traffic congestion during peak hours. Urban tunnels, especially the overall tunnel body section landscape environment, directly impact drivers' driving safety and road traffic safety. From the perspective of traffic aesthetics, excellent tunnel landscape design cannot only improve the effects of the road landscape and aesthetic value, but also help drivers form a good real-time line of sight to guide them and improve traffic safety [2]. The three-dimensional space form of the urban tunnel landscape comprises road facilities such as the tunnel's entrance, ceiling, side walls, road surface, lighting fixtures, signs and markings, and artificial structures formed by human processing of the natural landscape. Many researchers have conducted studies on the influences of lighting fixtures, traffic facilities and other landscape elements on visual features and have achieved some results [3]. Regrettably, the existing urban tunnel landscape design methods were made by designers and operators to design the parameters of the tunnel landscape or evaluate its design parameters only by biological indicators (such as eye movement), thus lacking a direct and systematic evaluation of the driver's driving status when driving a car through the urban tunnel, and failing to fully consider the safety of tunnel driving. The evaluation of the urban tunnel landscape can ensure the safe and regular operation of urban tunnels so that drivers can obtain a better driving experience, thereby improving the operation level of the tunnels. From the perspective of tunnel entrance landscape design, many experts and scholars have assessed the impact on drivers' comfort and safety during driving [4; 5; 6; 7]. Regarding tunnel landscapes, most evaluations primarily focused on single factors, such as lighting and induction systems to assess their influences on the driving experience [8], while a comprehensive evaluation of tunnel landscapes was rarely conducted. Due to the prolonged duration of vehicle passage, the tunnel body section constitutes the primary component of a driver's urban tunnel driving experience, and the landscape design of the body section in urban tunnels has significant impacts and effects on the overall driving experience. According to the literature survey, altering the physical attributes (such as color and pattern) of the tunnel body sections impacts drivers' physiological indicators, thereby enhancing their speed perception ability, improving line-of-sight guidance within tunnels and ultimately enhancing driving safety [9]. Biomass serves as an external manifestation of human psychological changes, which is beyond subjective control. Evaluating drivers' psychological changes through objective and accurate means is crucial. Consequently, some scholars directly investigated drivers' biomass (such as ECG, EEG, reaction time and visual efficacy) to assess their safety and comfort by observing dynamic perception or biomass variations during driving [10; 11]. As early as 1974, some researchers have used eye-tracking technology to record drivers' visual characteristics. These data focused on the partial eye movement features of drivers approaching tunnel entrances. According to the study, during the process of entering a tunnel, the drivers' gaze points gradually and frequently fixated on the entrance, from which the concept of a fixation point was proposed [12]. Afterward, research was conducted on the visual attention characteristics of drivers in the entrance section of tunnels. This study utilized an onboard video eye-tracking system to analyze visual parameters such as the fixation point density map, eye movement scan amplitude and average fixation time [13].