Does the adhesion decrease when driving in a tunnel?
2 Answers
When entering a tunnel, you should turn on the low beam and drive on the right side. There is no sunlight in the tunnel, and the air temperature is relatively low. The lower the temperature, the stronger the condensation of water. Therefore, the road surface in the tunnel is wet, which reduces the adhesion of the vehicle, so you should slow down. Extended information: 1. When the speed is low, the reason for the decrease in friction (i.e., adhesion) is mainly due to the reduction of the friction factor of the road surface caused by rainwater. 2. When the speed is high, the reason for the decrease in friction (i.e., adhesion) is mainly due to the high relative motion between the high-speed rotating wheels and the ground, which forms dynamic pressure lubrication and creates a thin layer of water between the ground and the wheels. At this time, the friction factor will decrease to a very small level, and the friction will also rapidly drop to a very low level. This is very dangerous because when the friction is extremely low, the car is very easy to lose control.
I remember last time driving through a tunnel, I did feel the tire grip was a bit worse. This might be because tunnels are more humid, with water accumulation or oil stains on the road, reducing tire adhesion. Once at night, I passed through a long tunnel where the humidity was so thick it felt like fog. When I braked, the car slightly skidded, but fortunately, I had slowed down enough to stabilize it. Experts say tunnel ventilation isn't as good as outside, so moisture easily condenses into a water film, reducing friction between the tires and the road. Plus, the dimmer lighting affects visibility, making reactions slower. So, I suggest slowing down below the speed limit before entering a tunnel, avoiding overtaking, and checking if the tire treads are deep enough—otherwise, it's even more dangerous in the rain. Occasionally cleaning dust and dirt accumulated under the car can reduce the risk of skidding. Getting home safely is what matters most.
