Structural engineers have been called in after a lorry became wedged under the flyover which carries the A14 over Huntingdon railway station early this morning.
The incident happened at about 2am when the vehicle using Brampton Road tried to get under the flyover - which had a height restriction imposed after steel reinforcements were added to the underside of the structure.
The vehicle was later removed and engineers were called in to examine the flyover and temporary traffic lights were put in place.
There were major tailbacks from the scene running back through Godmanchester.
A police spokesman said the incident was reported at 2am by the ambulance service.
"A lorry was wedged under the middle of the bridge," the spokesman said.
Police remained at the scene until 9.20am.
The flyover will be demolished as part of the A14 upgrade and the steel reinforcements were added, reducing the height of the bridge, to keep it in operation in the meantime.
Traffic remained flowing on the A14 itself.