The treaty of 2008 between Germany and Denmark provides that the hinterland connection to the Fehmarnbelt link is to be expanded on the German side, but the Fehmarnsund Crossing connection should remain two-lane road and single-track railway.

[2] In March 2020 the Federal Ministry for Transport and Digital Infrastructure and Deutsche Bahn announced[3] that they compared all investigated variants and opted for an immersed tunnel for road and rail (estimated cost: 714 million euros) and that the Fehmarnsund Bridge is to be preserved.

The design of the tunnel is very similar to the standard elements of the Fehmarn Belt Fixed Link currently being built.

This is to be expected since both tunnels have been designed by groups with COWI involved.

Also, suggestions have been made to preserve the factory for future projects.