A part of the A14 was closed in both directions last night following fears a man was going to jump from a bridge.
This happened about 21:30 on a bridge spanning the road near Hemingford Grey.
A police spokesman said: "We received a report expressing concern that a male was on the bridge, and there was concern about his safety.
While the incident was under way, the trunk road was closed in both directions between the St Ives Galley Hill junction and Hemingford Grey. Motorists were advised to find other routes.
The road re-opened around 22:00,