A road outside of a built-up area has just one lane in the direction of travel. Which trucks have to maintain such a great distance between them and the vehicle ahead, that an overtaking vehicle can pull back into lane?

Your answer is correct because according to German traffic regulations, trucks with a gross vehicle weight rating over 3.5 tons must maintain a sufficient distance from the vehicle ahead. This rule is in place to ensure that there is enough space for an overtaking vehicle to safely return to its lane without endangering itself or others on the road. The distance helps prevent accidents and allows for smoother traffic flow, especially on roads with only one lane in each direction where overtaking is limited. Following this regulation is crucial for maintaining safety and compliance with traffic laws.