Avon and Somerset Police are appealing for witnesses following the fatal collision involving two lorries on the A372 near Podimore.
The police said: “One of the vehicles appears to have been struck by a crane fixed to the other lorry and ended up in a roadside ditch.
“The driver of the lorry in the ditch – believed to be in his 40s – suffered serious head injuries and died later at the scene.”
The road was closed to enable a detailed examination of the scene by collision investigators.
The Health and Safety Executive and the Vehicle and Operator Services Agency have been informed.