The M5 has been closed in both directions following two separate collisions, causing major delays for rush hour traffic.
National Highways South West said the motorway was shut at about 23:00 BST on Thursday in both directions between J27 at Sampford Peverell to J28 in Cullompton in Devon.
Devon and Cornwall Police said the road would remain closed on Friday morning due to “extensive investigations”.
Bristol Airport has advised people to seek an “alternative route”.
Devon County Council said there was higher than usual volumes of traffic around Cullompton and Willand due to the emergency closure and advised motorists to use alternative routes and allow extra time for journeys.
National Highways said at 07:50: “Police have advised the road will remain closed most of the morning due to extensive investigations.”
