## 3 Materials and Methods
### Developed Scenarios and Limitations  
The land topography and geometric properties of the computer-animated road were modelled based on a section of the \"Zigana Tunnel\" in Trabzon, Turkiye. The \"Zigana Tunnel\" is a twin-tube tunnel, with a total length of 29 km (14.5 km for each tube). This makes it the longest twin-tube tunnel in Europe and the third longest in the world (13) (Figure 4). Figure 3: Study methodology and work steps. Figure 2: A typical visual of a driving simulator. The simulator landscape was designed to replicate the real surroundings of a tunnel road, incorporating various tunnel infrastructures and features. Objects such as tunnel lighting, wall paintings, traffic signs, advertisement boards, shoulders, stop lanes, and ventilation shafts were placed to create an accurate tunnel road environment. During the tests, the simulated route covered 6.3 km and consisted of two lanes in each direction, with a posted speed limit of 80 km/h and minor grade changes throughout the tunnel. A 0.6 km section of the test route included a horizontal curve. In all experiments, the weather conditions were determined as sunny and the traffic volumes were chosen as about 500 vehicles/h (average real traffic volume) obtained from the real-site observations from the Zigana Tunnel during peak hours. As no congestion or heavy traffic was observed during the actual field observations in the Zigana tunnel, a scenario similar to the real situation was prepared for this study. To ensure that all drivers were rested and under similar fatigue conditions during the tests, the tests were conducted in the morning hours to avoid any fatigue effect on the drivers. The current simulator has not been designed with two or three-axis lateral movement. Therefore, the feeling of reality for the drivers was provided by the wide field of view, real external sounds, real vehicle and its accessories (steering, accelerator and brake, indicators, etc.) and the 3D quality and realism of the scenarios (real tunnel design, traffic flow, vehicles, environment, etc.). The layout of the designed test route is shown in Figure 5.  
To create a realistic tunnel road impression, actual roadside photographs were taken along the route and superimposed using the software. The real locations of the tunnel road and all existing objects were accurately embedded into the simulation. In all experiments, traffic volumes were deliberately set to free-flow conditions, reflecting the typical traffic situation on the examined tunnel road. The study identified three distinct scenarios. In the first scenario (S-1), vehicles pass through a section of the tunnel where the lighting is blue sky. There are no parked vehicles or accidents in this scenario, and vehicles drive through the tunnel on the road section illuminated by blue lights (Figure 6a). In the second scenario (S-2), vehicles encounter red tunnel lights and a stopped van in the right lane (Figure 6b). After passing the stopped  
Figure 4: Project details and real images from Zigana Tunnel [40]. vehicle, the tunnel lighting changes to green at a certain distance. In the third and final scenario (S-3), vehicles first encounter flashing red warning lights along the sides of the tunnel. They then proceed through a section with red tunnel lights, where the right lane is blocked by road cones and a stationary lorry, leaving only the left lane open. After passing through this hazardous section, the tunnel lighting changes back to green (Figure 6c). The geometric characteristics of these three proposed scenarios are provided in Table 1.  
Figure 5: The simulated route of the Zigana Tunnel. Figure 6: Proposed scenarios for the driving tests. (**a**) Vehicles drive through a section illuminated by blue sky lights, with no parked vehicles or accidents; (**b**) Vehicles encounter red lights and a stopped van in the right lane, then the lights change to green; (**c**) Vehicles face flashing red warning lights, a blocked right lane, and pass through a hazardous section before the lights turn green.