You want to drive straight ahead. Where should you position yourself in this situation?

You answered correctly by choosing to position yourself on the right behind the truck when you want to drive straight ahead. In German traffic rules, lane positioning is important to clearly indicate your intended direction and to follow road markings.

If the right lane is marked only for turning right, you should not stay there if you want to go straight. Instead, position yourself in the lane that allows straight driving, usually the left or middle lane if available. However, in the presented situation, the right lane was still initially for straight or right-turn movements, so staying behind the truck on the right was appropriate.

Being behind the truck and not directly behind the motorcycle is safer and more predictable, as trucks typically maintain steady speeds and predictable movements. The motorcycle may maneuver more quickly or change lanes.

In short, you should choose the lane that corresponds to your intended direction and maintain a safe, predictable following position — behind a larger vehicle in your lane if possible. This helps ensure safety and clarity at intersections and lane changes.