A four-vehicle crash on the M49 has left two people in a critical condition hospital.
Emergency services were called at about 4.15pm on Friday 13 May to the incident which involved a Mercedes Sprinter van, an Audi A3, a Ford Focus and a Mazda 2, all travelling south.
Five people were involved and two drivers remain in a critical condition in hospital.
A passenger from one of the cars was discharged after treatment while two other drivers were treated at the scene by ambulance crew.
The motorway was closed southbound between junction 22 of the M4 and junction 18 of the M5 until the early hours of today (14 May)
Avon and Somerset Police has now issued an appeal for witnesses.
A spokesperson said: "If you were on that stretch of motorway at about 4.15pm on Friday and saw the collision or have any dashcam footage which could help, please call 101 and give the reference 5222113538."