The Army & Navy flyover is closed due to a two-vehicles crash on the flyover.
The crash is causing delays on all approaches to the Army and Navy roundabout and resulted in somebody being trapped in their car.
A spokesman for Essex fire service said: "Firefighters were called to assist at the scene of a road traffic collision on the flyover at Chelmsford's Army and Navy roundabout this afternoon.
"Crews reported on arrival that two vehicles had been involved in the incident, which had left one person trapped.
"Firefighters freed the person by 2.35pm, before leaving them in the care of the Ambulance Service."
A spokesman for the East of England Ambulance Service Trust said: "We were called at 1.55pm today to this collision.
"An ambulance officer and two ambulance crews were dispatched. They are assessing and treating three patients with chest pain."
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