The A30 in the west bound direction is blocked at Illogan after reports of a road traffic collision involving five vehicles.
It is not yet known if there are any injuries after the incident, although the ambulance service have been called to the scene.
A spokesperson for Devon and Cornwall Police said: “Police were called at around 7.50am on Thursday January 9 following reports of a multi-vehicle collision on the A30 westbound near Illogan.
“It is believed five vehicles were involved.
“The ambulance service has also been called and a road closure put in place covering both lanes westbound.”
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