A driver has been treated for shock after his bus came off the guided busway tracks in Cambridgeshire.
Police said it happened just after 15:00 GMT and no passengers are thought to have been injured.
Stagecoach said the driver misjudged an entrance to the busway between Swavesey and Longstanton and he was looked over by ambulance crews at the scene.
The firm's managing director Andy Campbell said services were still running, but diversions were in place.
Witnesses said the bus had been left at a 45-degree angle on the busway.
The concrete-tracked busway opened last year and runs services between Huntingdon and Trumpington, south of Cambridge.