actually on the accerlation lane on the german autobahn there is no requirement for a zipper. (https://dejure.org/gesetze/StVO/18.html https://dejure.org/gesetz

actually on the accerlation lane on the german autobahn there is no requirement for a zipper. (https://dejure.org/gesetze/StVO/18.html https://dejure.org/gesetze/StVO/18.html (3)) The ruling was also applied inside the OLG Köln: 24.10.2005 - 16 U 24/05) but there are other courts that ruled like that. (The same ruling applies to "Bundesstraßen")