The M5 was closed by emergency services after a heavy collision near Taunton and an ambulance is on its way to the scene.
All lanes south between Junctions 24 and 25 for Bridgwater and Taunton were closed as a result of the collision, which was reported at 8:40.
The transport service provider Inrix suggests that traffic can not pass due to the accident and that vehicles are temporarily held on the north side.
UPDATE: These are the diversions for traffic
An unconfirmed report from a motorist was in traffic near the incident that came up Bristol Live , said several vehicles were involved.
Images of traffic cameras show significant traffic jams and delays in the area.
Highways England has meanwhile tweeted to alert drivers to the incident and inform them that the M5 is just closing.
In a statement on social media Highways said: "The road is closed because of a serious collision.
"Ambulance aircraft are on the road and emergency services are on-site. Please consider alternative routes where possible and watch for approach."
We report on this incident in our live blog. To see the latest updates of M5 lane closures and traffic obstructions, scroll down.
If you've seen the incident or have pictures or videos of it, contact the Bristol Live Newsroom on 0117 934 3331.
You can also get the latest traffic information when you join this particular Bristol Traffic and Travel Facebook Group.
READ MORE: The M5 is notorious for accidents and delays – earlier this year, a hero rider ran over three lanes to rescue a motorcyclist who last month 50 meters after leaving the lane crashed chaos as the new lane did not set. There are also plans for a new M5 intersection north of Bristol.
Police have previously explained why highways are closed in a fatal accident for so long.