The A505 has now fully reopened following an earlier crash near the Duxford Imperial War Museum.
Emergency services were called at about 4.45pm after a crash involving a motorcyclist and a lorry close to the turning for Thriplow.
Initially the road was closed by police in both directions between Junction 10 of the M11 for Duxford and the B1368.
The westbound carriageway towards Royston remained shut, but has now reopened.
Two ambulances, the Hazardous Area Response Team, an ambulance officer and the East Anglian Air Ambulance medical car had all attended the scene, and an ambulance spokeswoman said a man – the motorcyclist – was treated for serious leg injuries. He has been taken to Addenbrooke’s Hospital in Cambridge for further care.
Another person was also treated at the scene and taken to Addenbrooke’s.
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