What is the right course of action?

Your answer to reduce speed is correct because in certain situations, such as approaching slower traffic or a congestion point, it is important to slow down to maintain safety and avoid accidents. According to German traffic rules, you should always adjust your speed to the current traffic and road conditions.

Continuing at the same speed or moving immediately into the right lane might not be safe if the right lane is occupied or if you need to prepare for an upcoming hazard. Reducing speed helps you maintain control and react appropriately. This rule ensures smooth traffic flow and safety on the road.