The A11 southbound was closed after a car crashed into the central reservation on the dual carriageway.
The crash happened between Barton Mills and Elveden at about 7.50pm.
A black Fiat Ibiza was involved but no injuries have been reported.
A police spokeswoman said: "Units remain at the scene following a crash on the A11.
"The vehicle is currently awaiting recovery and the road is expected to reopen in about an hour's time."
The fire service also responded to the crash, with units from Thetford, Bradford and Mildenhall attending.
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