The Nene Parkway was closed northbound for five hours today after a lorry collided with a bridge.
The accident happened near the junction at Orton Malborne.
It is not believed anyone was injured, but the road was closed for around five hours while repairs to the bridge are made.
A Cambridgeshire police spokesman said: “We were called at 8.49am with reports of a lorry carrying a digger striking a bridge on the Nene Parkway in Peterborough. The lorry was travelling from the direction of Thorpe Wood to Hampton and has hit the bridge at the slip road for Orton Malbourne.
“No injuries have been reported although there is extensive damage to the bridge.”
Buses were diverted while the work takes place.
A Peterborough City Council spokesman said investigations were taking place to see if the bridge was safe.
The spokesman said: “The Nene Parkway has been closed northbound (towards Thorpe Wood) from junction 3 (Hampton main roundabout) to just after junction 2.
“In addition, the roundabout which connects Morley Way with Malborne Way is closed in both directions.
“We are currently clearing the road of concrete debris and hydraulic oil and checking the safety of the bridge. We think the damage to the bridge is cosmetic and not structural so we expect the road and roundabout to reopen this afternoon.”
The road reopened fully at around 2pm. However, overnight closures will be necessary to carry out further repairs.