A two-year-old boy was killed in the accident on the M180 on Saturday.
The boy was a back seat passenger in a Vauxhall Meriva which left the carriageway and overturned between Forest Pines and the M181 junction at 8.45am.
The driver of the car, a 28-year-old man and the front seat passenger, a 22-year-old woman, as well as a second back seat passenger who was a three-year-old boy, were all taken to hospital with minor injuries.
The family are from North East Lincolnshire.
The motorway was closed westbound for several hours after the crash and the air ambulance was also called to the scene.
Any witnesses are urged to call Humberside Police on 101 quoting log 186 of Saturday, December 13.