A 38-year-old woman is in hospital with serious injuries, that are believed to be life-threatening, following a collision on the M66 yesterday afternoon.
Three children were also taken to hospital with serious injuries.
A 22-year-old man was arrested at the scene on suspicion of causing serious injury by dangerous driving.
He remains in custody for questioning.
Emergency services were called to the scene on the southbound carriageway between junctions 3 & 4 at around 3 pm.
Police are now appealing for witnesses and information.
Sergeant Matt Waggett from GMP Serious Collision Investigation Unit said: “I would like to thank the members of the public who selflessly helped at the scene and called 999, as well as those who assisted when police and emergency services arrived on scene.
“I urge anyone who may have witnessed this incident to please come forward and share any footage, dashcam or mobile footage, with police.
"No matter how small you think it is, it could prove vital to our investigation."
Information can be shared by calling GMP's Serious Collision Investigation Unit on 0161 856 4741 quoting incident 2254 of 13/05/2023.
A report can also be made via GMP's website: www.gmp.police.uk
Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.
The new Bury NeighbourHub has opened to support residents with work, skills, health, and wellbeing
Cardinal Langley students celebrate 'exceptional' A-Level and BTEC results
Veterans group to take over cafe and community hub at Denehurst House
Hopwood Hall College students celebrate Results Day success
Bury residents asked for views on 10-year housing strategy
Seven more Rochdale schools to offer free breakfast clubs
Rochdale Netball Club joins Rochdale AFC under new identity
Roch Valley Radio presenter Ian Foran appointed Rochdale AFC Sports College head coach
93-year-old former police officer returns to Rochdale station
Burnley man banned from keeping animals after dog found emaciated in Rochdale home
OMD play first Rochdale show to sold-out Town Hall Square crowd
Mayor Faisal Rana reflects on busy start to mayoral year
