The two people killed were a married couple whose Nissan Qashqai car was crushed when the bridge came crashing down without warning.

“It suddenly collapsed, we were all in shock,” said a driver named Francesco, who had to brake suddenly when the bridge came crashing down.

“Then we realized that underneath the collapsed bridge there was a car with people inside. It was terrible. It was a miracle that we survived. A woman in front of me slammed on the breaks and stopped just 10 metres from the bridge. It all happened so quickly.”

Engineers were working to widen the motorway and the bridge was propped up by temporary support pillars.

The disaster was caused by “the collapse of a temporary structure that was supporting the bridge, which had been closed to traffic,” said the national roads authority.

The two injured were road workers who were employed at the site. They were taken to a hospital in Ancona. Traffic on the motorway had to be closed in both directions.