The A41 was temporarily closed yesterday due to concerns about the welfare of a person.
Police were called to the dual carriageway in Leavesden just before 8pm (May 20).
Hertfordshire Constabulary has the confirmed the incident was resolved safely.
A spokesperson said: "Police were called at 7.59pm to reports of the concern for welfare of a male at the Ashfields bridge.
"The incident was brought to safe conclusion and road closures were lifted at around 8.30pm."
Police initially posted on social media: "We are currently dealing with an incident on North Western Avenue in Watford, the road has been closed, drivers are advised to avoid the area."
It was the second road closure in the area yesterday.
A woman in her 80s was seriously injured after she was struck by a vehicle in Hempstead Road, near the junction with Courtlands Drive.
Emergency services were called at 1.39pm with an air ambulance attending.
Read more: Elderly woman 'seriously injured' after being hit by car in Watford
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