One thing, Veefer, which may be new to you is that yellow road markings cancel and superscede any other (generally white) markings on the road. Yellow markings are often used at road works (Baustelle). There is generally a speed limit at Baustelle.
Another thing is that when two lanes filter into one, they use the Reisverschüßverfahren (zip procedure). In other words, vehicles from each lane take it in turn to join the single flow.
To try to follow the guy immediately in front of you, in your lane, without giving way to the chap in the other lane, will be frowned upon - generally by somebody pointing their fore finger at the side of their head (Vogelzeigen = show you the bird (brain))