A major route has been closed in both directions after a lorry caught fire on the carriageway.
Cambridgeshire Fire and Rescue Service said it was responding to an incident on the A14 near Bar Hill, outside Cambridge.
It said both the eastbound and westbound carriageways were closed while crews tackled the fire.
Motorists were asked to avoid the area for at least four hours and find alternative routes.
BBC reporter Matthew Webb, who saw the incident, said the lorry appeared to be transporting hay.
He said there were five fire engines at the scene and a crew from Suffolk.
It was the second time on Monday that crews tackled a fire on the A14 in Cambridgeshire.
Earlier a van fire caused tailbacks as thick, black smoke drifted over the carriageway between Swavesey and Ermine Street.
