A man has been arrested over a multi-vehicle crash that closed the M1 for eight hours and left a man seriously injured.
Highways England shut the motorway southbound in Nottinghamshire between junctions 28 for Kirkby-in-Ashfield and 26 for Nuthall on Saturday.
A 27-year-old was arrested on suspicion of dangerous driving and is in hospital.
A 48-year-old man is in a critical condition in hospital, police say.
Nottinghamshire and Derbyshire police forces thanked members of the public who came to the aid of those involved in the collision at 05:30 GMT.
Investigators have appealed for information and "crucial" dash camera footage.