O-Bahn
/ˈəʊbɑːn/(also O-bahn)
noun
A track on which a bus, by means of special locking wheels, may run without needing to be steered; a bus or bus service which uses such a track.
Origin
1980s; earliest use found in The Financial Times. From German O-Bahn from O- (in Omnibus bus) + Bahn (railway) track.