What guided busway in Adelaide, Australia, opened in 1986?

The guided busway in Adelaide, Australia, that opened in 1986 is the O-Bahn Busway.

Adelaide adopted the system to serve its rapidly growing northeastern suburbs after plans for a light-rail extension were abandoned. Construction began in 1983, and the first stage—from the city toward Paradise—opened on 9 March 1986. The route was completed to Tea Tree Plaza in 1989.

An O-Bahn is not a railway: specially modified buses run on concrete tracks, using small guide wheels connected to the steering system. The 12-kilometre Adelaide route combines the speed and separation of a dedicated transit line with the flexibility of buses, which can leave the track at interchanges and continue on ordinary streets without requiring passengers to transfer.

The name comes from German words associated with buses and paths or railways. Adelaide's system is often confused with ordinary bus rapid transit, but its distinctive guided track and steer-by-guide-wheel technology make it a specific type of busway.