In **tunnels with one lane for each direction**, overtaking is prohibited. This is because, in these situations, the vehicle you wish to overtake only has one lane in its direction of travel. Overtaking under these conditions can be very dangerous, as there is not enough space to maneuver without encroaching on the opposite lane, which could cause an accident. Additionally, visibility in tunnels is often limited, increasing the risk of collisions. For these reasons, the regulations prohibit overtaking in tunnels with traffic in both directions and only one lane per direction.