Where can you stow your baggage so that you do not increase your fuel consumption unnecessarily?

Stowing your baggage correctly is essential to ensure optimal fuel efficiency and vehicle safety. According to German traffic regulations, it is advisable to store luggage in the boot or behind the front seats. This is because items placed in these areas are less likely to affect the vehicle's aerodynamics, leading to better fuel consumption.

On the other hand, using a roof-rack increases drag and weight, which can negatively impact fuel efficiency. Therefore, the combination of options 1 and 2 is correct because they represent the most efficient and safest locations for stowing baggage while driving. It is important to adhere to these guidelines not only for fuel efficiency but also to maintain proper vehicle handling and stability on the road.