In Spain, there are over 400 tunnels, totaling about 200 kilometers. Because of this, the DGT (Directorate-General for Traffic) has shared some recommendations for driving safely, properly using lights, maintaining distances, and being mindful of the “screen effect” when exiting them.
So, take careful note of the tips if you're thinking about hitting the road these days when there's heavy traffic.
Lights and sunglasses
Before entering a tunnel, it is mandatory to turn on your lights (and you must remember to turn them off when exiting), no matter how short the tunnel is. The DGT indicates that:
“It’s essential, for being seen and for seeing, especially in the first few meters where the driver’s eye takes time to adjust to the change in light. And if you’re wearing sunglasses, take them off when going inside and put them on when going outside, where you might be blinded.
Safety distance and overtaking
In tunnels with two-way traffic, overtaking is prohibited unless there is more than one lane for your direction of travel. In any case, you must maintain a safe distance of at least 100 meters from the vehicle in front.
Braking
The asphalt in tunnels usually has less grip than on outdoor roads. And it is precisely because of this that the braking distance can be longer, which makes it mandatory to take the distance recommendations we gave you in the previous point very seriously.
Circulation stopped
In cases where traffic stops inside the tunnel, you must stop at a safe distance from the car in front of you. Do not leave the car, turn on the Emergency signal, turn off the engine and leave the parking lights on.
Screen effect
When driving through tunnels, an effect called the “tunnel effect” occurs, which the DGT explains:
“In case of wind, upon exiting the tunnel, the vehicle may be displaced laterally by gusts of wind. Therefore, you must exit prepared and alert, gripping the steering wheel firmly and turning the wheels slightly in the direction from which the wind is blowing.
