The M4 westbound near Bath has been closed between Junction 18 at Tormarton and Junction 19, Bristol/M32, due to a significant lorry fire.
Traffic caught within the closure is being released along lane three of the motorway, passed the scene.
An update from National Highways at 8.49pm said there were delays of 45 minutes above the usual travel time on the approach to J18 westbound.
National Highways said due to the intense nature of the fire, the carriageway was closed while the fire service initially tackled the blaze.
Traffic Officers are assisting the emergency services with traffic management.
Hay bales were being removed from the vehicle with Avon Fire & Rescue Service crews remaining on scene to dampen them down.
Avon Fire & Rescue Service said crews from Bath, Yate, Temple, Patchway and Radstock have been in attendance.
They used three 45mm jets, one high pressure hose reel and drag forks to extinguish the fire. Respirators and breathing apparatus were worn for safety.