Police are warning drivers to take alternative routes following a fire on the guided busway.
Officers are currently dealing with a crash near the level crossing in Station Road, Longstanton, and are warning drivers to avoid the area whilst they deal with the incident.
Fire crews were called at about 9.30am to a fire on the B1050 at the crossroads of Longstanton and Willingham.
Three crews from Cambridge, one crew from Cottenham and one crew from St Ives are currently at the scene of a fire involving a bus and a car.
A spokesman for Cambridgeshire Fire and Rescue Service said: "Buses using the guided busway have been diverted and will be using other routes, so please expect delays."
Bus operator Stagecoach also confirmed it was aware of the situation and was "dealing with it".