A three-mile stretch of the A30 is closed both ways between Treleigh and Tolvaddon in Cornwall. The road is often used by tourists to reach seaside resorts including Portreath and Gwithian.
A bridge above the dual-carriageway taking a local road to and from Tolskithy has also been shut as part of the police investigation. The man’s body was found on the dual-carriageway near the structure at around 3.20am.
The man’s next-of-kin have been informed, reports Cornwall Live.
No further details about the man, such as his age, have been disclosed by the force at this stage.
A spokesperson for Devon and Cornwall Police said: “It is a serious incident.
“The road will be remaining closed for the foreseeable future.”
Southbound traffic is advised to leave A30 at Scorrier and join the A3047 to go through Treleigh and Tolskithy.
Northbound motorists can use this route or leave the A30 earlier, join the A3047 at Treswithian and go through Camborne.
But police have warned drivers these roads are congested as a result.