The M5 has been closed due to a police incident, with drivers being advised to take alternative routes.
The motorway is blocked in both directions near Bristol between junction 18 for Avonmouth and junction 19 for Portbury, Avon and Somerset Police said.
Traffic management site Inrix is reporting long delays, with congestion reaching junction 20 for Clevedon northbound and junction 17 for Cribbs Causeway southbound.
There is also heavy traffic on the A4 Portway into Bristol towards Hotwells as people divert away from the southbound closure and on the A370 towards Congresbury for people diverting northbound.
