The A64 westbound is closed between the B1257 and B1248 near Malton in North Yorkshire.
This is due to a shed load of concrete blocks from an overturned vehicle.
The blocks require specialist equipment to remove and this is being arranged. North Yorkshire Police and Highways England contractors are on scene.
A local diversion is in operation through Malton.
Road users intending on using this section of road and advised to allow additional time for their journeys.