The M5 motorway in Gloucestershire has reopened following a crash on Saturday which claimed four lives and left three people critically injured.
The road was shut after a lorry travelling south crashed through barriers and collided with two vehicles heading northwards, police said.
The southbound carriageway between junctions 16 and 14 reopened on Sunday morning, but one lane northbound will remain shut into Monday.
Drivers were warned to expect delays.
No details of the four people killed in the crash, which happened at 14:30 BST between junctions 15 and 14, have been released by police.
The injured woman and children were taken to Southmead Hospital and Bristol Children's Hospital where their conditions were described as "critical but stable".
The driver of the lorry was taken to hospital to be checked over as a precaution.
Supt Simon Ellis from Avon and Somerset Police said: "This was a horrific incident which has tragically claimed the lives of four people and seriously injured three others.
"Our thoughts are very much with their families and friends during what is an extremely difficult time."
He praised the emergency effort following the crash, and added: "I'd also like to once again praise the members of the public who courageously went to the aid of those involved in this collision and in some cases rescued them from their vehicles.
"Their bravery and composure must be commended."
Supt Ellis said one lane would remain closed but he expected "the carriageway to reopen completely" later on Monday.
Earlier, Insp Mark Whitfield said the 18-tonne lorry had collided with the two cars killing three people from one vehicle and one person from the other.
He said: "The main issue for us is why the lorry has crossed over from the central reservation.
"There are a number of lines of inquiry we're looking at, one of which will be if the vehicle had defects."