You want to tow a singe-axle caravan trailer behind your car. What must you check?

When towing a single-axle caravan trailer, it's essential to check both the permissible trailer load and the permissible coupling of the car, as well as whether additional rear-view mirrors are needed due to the trailer's width.

1. **Permissible Load and Coupling**: German traffic regulations specify that you must ensure that neither the trailer load nor the coupling exceeds the limits set for your vehicle. This is crucial for safe towing and preventing accidents.

2. **Rear-View Mirrors**: If the width of the trailer is greater than that of the car, additional rear-view mirrors are mandatory to ensure proper visibility and road safety. This requirement is part of the regulations to prevent blind spots when driving with a trailer.

The last option regarding the trailer being licensed to transport passengers is not relevant in this context. Therefore, focusing only on the first two checks is necessary to comply with German traffic rules and ensure safe operation while towing a trailer.