Traffic was brought to a halt on the A120 near the Ardleigh interchange this afternoon following an incident involving four vehicles.
The crash happened at 1.30pm today and came after a minor shunt involving two vehicles on the northbound carriageway.
It is believed motorists on the southbound carriageway were slowing down to look at the scene, which caused the incident.
Highways officials were called to help at the scene and the road was re-opened shortly after, but traffic is still moving slowly on the road.
A police spokesman said one woman in her 20s was treated at the scene for minor injuries.
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