Which basic code of conduct must you observe in a tunnel?

Your selected combination of answers is correct because it reflects essential safety rules for driving in tunnels as outlined in German traffic regulations.

1. Driving with dipped headlights, even during the day in well-lit tunnels, increases visibility and helps other drivers see your vehicle, which is crucial in confined spaces.
2. Prohibiting U-turns in a tunnel is important for maintaining safety and traffic flow. U-turns can lead to dangerous situations and obstruct the movement of other vehicles.
3. Following instructions from tunnel personnel is vital, as they are trained to manage traffic and ensure the safety of all drivers in emergencies or unusual situations.

Observing these rules helps prevent accidents and ensures a smoother traffic experience in tunnels.