What should you do when entering a tunnel on a sunny day?

When entering a tunnel on a sunny day, it is important to slow down to allow your eyes to adjust to the significant change in light levels. The transition from bright sunlight to the darker environment of a tunnel can temporarily impair your vision. By reducing your speed, you give yourself more time to adapt, which is essential for maintaining awareness of your surroundings and responding safely to any changes in the road or potential hazards within the tunnel.

Ensuring a gradual adjustment to the lighting conditions can help prevent sudden surprises, such as obstacles or other vehicles, that may be more difficult to see immediately upon entering a darker area. This awareness is particularly crucial in tunnels where visual cues differ significantly compared to outside conditions.