In which situation is it purposeful to use an active lane change assist system?

The active lane change assist system is especially useful in specific driving environments. On motorways and motorway-like roads, these systems can help ensure safe lane changes by monitoring surrounding traffic and assisting the driver in making informed decisions. This is crucial because of higher speeds and the need for quick yet safe maneuvers.

However, using the system on roads without markings is not recommended. These roads can lack necessary references for the assist system to function correctly, leading to potential safety risks. Thus, it's important to only use lane change assist functions where they are effective, which is why options 1 and 2 are the correct choices. This aligns with the principles of ensuring safety and effective driving practices as outlined in German traffic regulations.