Does the road adhesion decrease when driving in a tunnel?

[Silva]

Road adhesion does decrease when driving in a tunnel. The decrease in adhesion mainly refers to the impact of airflow within the tunnel on the vehicle, which reduces the friction between the tires and the road surface. Before entering a tunnel, there are traffic signs indicating width and height restrictions. Drivers must adhere to these warning signs. When passing through a culvert, it is necessary to reduce speed appropriately and check whether the vehicle's load height is within the permitted range indicated by the traffic signs. If necessary, get out of the vehicle to inspect and confirm before proceeding slowly. When approaching an uncontrolled single-lane tunnel, carefully observe both the inside of the tunnel and the entrance at the other end. If there are already vehicles inside the tunnel, take the initiative to stop and yield. If vehicles are about to enter from the other end, use high beams to signal. Once the oncoming vehicle enters the tunnel, stop immediately. If the other vehicle yields, proceed promptly. When within 50 meters of the tunnel entrance, turn on the headlights, width lights, and taillights, and check the speedometer to drive at the speed indicated by the tunnel entrance signs. Maintain a safe following distance to ensure sufficient space for avoiding hazards. Generally, a distance of over 100 meters should be kept when driving in a tunnel. For longer tunnels, follow the posted guidelines to maintain the appropriate safe driving distance. Avoid using high beams. Prolonged use of high beams at night can affect oncoming and preceding vehicles, as high beams can cause temporary blindness to drivers. The difference in light levels inside and outside the tunnel already makes it difficult for drivers to see, and the additional glare from high beams increases the risk of accidents. Therefore, high beams should be avoided.