Motorists faced four miles of delays on the A1 southbound towards the A605 at Alwalton this morning.
The delays were due to an event at the East of England Arena and Events Centre, according to Cambridgeshire County Council’s Highways Service.
There were also said to be some delays northbound.
According to the arena’s website it is hosting Plantworx - featuring live construction applications and working machinery - and Railworx - a show about the working railway systems and civil engineering - today, tomorrow and Thursday.
The delays have now cleared.