A major multi-agency operation is continuing on the M5 in South Gloucestershire following a fatal collision earlier today.
A lorry travelling on the southbound carriageway reportedly drove through a central reservation and into oncoming traffic, hitting several vehicles, including a motorbike before ending up in a ditch on the side of the road.
Four people have died and a woman and two children are seriously ill in hospital after a lorry smashed through the central reservation on the M5.
The lorry driver was also taken to hospital to be checked over as a precaution.
Dr Amer Hamed who was in a auto behind helped a GP and other medics tend to the injured woman before paramedics arrived six minutes later and rushed her to hospital.
Cardiologist Amer Hamed, who was in a auto travelling "10 to 20 seconds behind" the crash, told the BBC: "There was a lorry involved and at least two other cars".
South Western Ambulance Service Trust say a critical care team and a dozen ambulances are the scene of the crash dealing with the wounded.
Police are asking people to avoid the area.
Highways England says traffic is trapped for around five miles.
The motorway is closed in both directions after the crash, which happened at about 2.30pm on Saturday.
He said: "There was a lorry involved and at least two other cars".
He said motorists who had been stuck on the carriageway for several hours were being "very helpful". "One was absolutely destroyed and another had flipped over".
Dr Hamed added: "People are helping as much as they can".
"There are now 13 ambulances at the scene including a critical care team".
The M5 is still closed northbound between J16 and 14.