You want to transport your holiday luggage on the roof of your fully occupied car. What must you observe?

The combination of options you selected is correct because both are essential for safely transporting luggage on the roof of your vehicle.

Observing the vehicle manufacturer's roof load specifications in the operating manual ensures that you do not exceed the design limits for the roof, which could affect vehicle stability and safety. Exceeding these limits can lead to reduced control and increased risk of accidents.

Additionally, checking the gross vehicle weight rating of your car is crucial because it represents the maximum weight the vehicle can safely carry. If your roof load, combined with the weight of the passengers and any other cargo, exceeds this limit, it can lead to serious safety issues and may violate traffic regulations.

In contrast, the roof load specifications in the registration certificate Part I, while relevant, are not pivotal to this specific question because they typically reiterate information already found in the operating manual or do not provide additional safety details necessary for this situation.

Understanding and adhering to these requirements is part of responsible vehicle operation and is enforced under German traffic laws to ensure both driver and passenger safety.