Devon and Cornwall Police are urging motorists to avoid the A30 at Upottery.
An overturned bin lorry, which knocked down a tree, is currently blocking the carriageway. Recovery crews are reportedly on the scene.
Devon and Cornwall Police told EastDevonnews.co.uk in a statement: “At approximately 8am, a bin lorry overturned on to its side completely blocking the west bound carriageway of the A30 near Upottery, Honiton, causing long tailbacks.
“The road has been closed and a diversion has been put in place. In the hands of Highways Agency.
“The lorry knocked a tree down which requires removing. A secondary collision occurred involving two cars.”
No one is thought to be injured in the incident.