A man was taken to hospital after he fell from a bridge.
The emergency services, including an air ambulance, were called to the A41 in the Watford area at around 11.30pm on Saturday night.
The report received by the East of England Ambulance Service was that a man had fallen.
He was treated at the scene and although the East Anglian Air Ambulance attended, he was taken by land ambulance to St Mary's Hospital in London.
His injuries are understood to be not life-threatening.
Police also attended the scene.
A Hertfordshire Constabulary spokesperson said: "Police were called at around 11.40pm on Saturday 18 July to report that a man had fallen from a bridge on the A41 in Watford.
"Officers attended, alongside colleagues from the ambulance service and road closures were put in place while they worked at the scene. The air ambulance also attended.
"The man was taken to hospital for treatment."
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