Travel along the A30 is at a standstill while firefighters tackle a coach fire.
A coach fire between the A395 and A389 has led to around two miles of traffic.
A spokesperson from National Highways South West said: "The A30 in Cornwall is closed westbound between the A395 near (Kennards House) and A389 near (Bodmin) due to a coach fire.
"Cornwall Fire and Rescue Service and Devon and Cornwall Police are in attendance. National Highways Traffic Officers are also on scene providing assistance with traffic management."
A diversion is currently in place hoping to relieve some of the road's delays, with Devon and Cornwall Police officers at the scene assisting with road closures.
A spokesperson from Cornwall Fire and Rescue said: "Fire crews from Bodmin and Launceston are in attendance at a coach that is fully involved in fire. All the occupants have evacuated. "Firefighters, some wearing breathing apparatus, are using two hosereels to extinguish the fire. " By 2.25pm, with fires extinguished, the carriageway was reopened. The spokesperson continued: "The fire has been extinguished. A replacement coach has collected the passengers. The A30 eastbound carriageway has been re-opened and fire crews have left the scene."