What should be observed in relation to route planning?

The selected combination of options emphasizes key aspects of route planning in the context of German traffic regulations.

1. The rules contained in the German summer holiday traffic regulations are crucial because they provide guidelines for traffic flow and safety during peak travel times, ensuring drivers are aware of increased congestion and special driving conditions.

2. The regulations on driving and rest periods are essential to ensure that drivers do not exceed allowed driving times, which helps prevent fatigue-related accidents. These regulations promote safety by enforcing mandatory breaks and rest periods.

3. Awareness of possible obstructions caused by roadworks is vital, as it enables drivers to plan alternate routes and avoid delays. This foresight contributes to smoother traffic flow and reduces the likelihood of sudden stop-and-go situations that can lead to accidents.

Considering all these factors together provides a comprehensive approach to safe and efficient route planning in accordance with German traffic laws. Each element plays a significant role in ensuring not just compliance, but also the safety of all road users.