There are plans to build a new road crossing of the Oslofjord between Horten and Moss, which would replace the Moss–Horten Ferry. It could include a connection of the Vestfold Line with the Østfold Line. One alternative was a suspension bridge across Drøbaksundet, which could be built to accommodate trains and feature a main span of . A bridge or tunnel crossing further south would require more advanced technology and presumably consist of combination of various bridge technologies, including as a pontoon bridge or a submerged floating tunnel.