The O-Bahn Busway is the world's longest, fastest and most heavily patronised guided busway. The O-Bahn (from Latin omnibus meaning "for all people" and German bahn meaning "train") design was originally conceived by Daimler-Benz to make use of former tram tunnels in the German city of Essen. While this plan did not come to fruition, the system was applied in the South Australian capital city of Adelaide to deliver services to its rapidly expanding north-eastern suburbs, replacing an earlier plan to create a tramline extension. The design is unique among public transport systems; typical busways make use of dedicated bus lanes or separate carriageways, while the O-Bahn runs on specially built tracks, combining elements of both bus and rail systems. The track is at a length of 12 kilometres (7.5 mi) and contains one station and two interchanges; Klemzig Station in Payneham, Paradise Interchange in Campbelltown and Tea Tree Plaza Interchange in Tea Tree Gully.