You need assistance on the autobahn. Which information does the arrow on the roadside marker give you?

Your answer is correct. The arrow on the roadside emergency marker on the autobahn points to the nearest emergency call telephone. In case you need assistance, you can follow the direction of the arrow to find the closest emergency phone, which is important because cell phone reception might be limited or battery could be drained. This system helps ensure you can quickly get help in an emergency situation on the highway. It is not meant to indicate car parks or exits, so always remember the arrow specifically guides you to the emergency call point.