Part of the M5 has been closed in both directions following a serious collision.
Emergency services were called to reports of a crash between junctions 14 and 13 close to Michaelwood Services at about 11:40 GMT on Tuesday, Gloucestershire Police said.
All lanes in both directions between these junctions are currently closed, and National Highways said they were expected to remain closed for the rest of the day.
Drivers are advised to find alternative routes, and police said officers will provide updates when more information becomes available.
The South West Ambulance Service said: “We sent one double-crewed land ambulance, an operations officer, a critical care car and the hazardous area response team to the scene.”
Motorists trapped in standstill traffic for almost two hours are now being directed onto a slip road.
National Highways said drivers currently face delays of up to 90 minutes.
“Please allow extra time for your journey due to delays on the approach and the A38 diversion route,” a spokesperson added.
