The A120 has been closed near Great Bromley in Essex while a heavy goods vehicle is recovered - causing miles of tailbacks.
According to Highways England, the road has been closed from the junction with the B1035 at Horsley Cross top the A133 at Great Bromley.
The agency is reporting delays of at least 15 minutes covering several miles of the westbound carriageway.
A spokesman added: “This closure is due to HGV recovery and Highways England has resources deployed working hard to restore normal conditions as soon as possible.”
They advised motorists to allow extra time to travel.
A diversion route has been set up to guide motorists around the road closure:
At Horsley Cross roundabout take the first exit onto the B1035 and continue through Tendring to the junction with the B1033.
Turn right onto the B1033, at Weeley continue in the A133.
At the A133 roundabout take the second exit follow the A133 through Frating Green and Elmstead Market to Colchester.
At Colchester continue on the A133 to the double roundabout with the A1232.
At the roundabout follow the A1232 for Ipswich and rejoin the A120 at Crown Interchange.
See www.trafficengland.com or @HighwaysEAST on Twitter for updates
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