A man has been arrested on suspicion of murder after a body was found on a motorway.
Part of the London-bound M20 near Ashford in Kent was closed between junctions 9 and 10 for nearly 24 hours after officers made the discovery at 6.05pm on Tuesday.
The person was pronounced dead at the scene.
Officers appealed for the driver of a silver Nissan Qashqai to come forward and a man handed himself in at a police station on Wednesday evening, Kent Police said.
He was arrested on suspicion of murder and remains in custody, a force spokesman said on Thursday.
No other details about the incident or the person who died have so far been released.
The incident caused hours of delays with between six and seven miles of queues stretching back to junction 11 and a diversion was in place.
The road reopened shortly after 4pm on Wednesday.
An accountant from Ashford told Press Association of his shock at the scene he saw while driving on to the coastbound stretch of motorway at about 6.20pm on Tuesday while emergency services were on the opposite side of the road.
The 21-year-old, who asked not to be named, said: "As I entered the motorway I expected to see a crash, when I suddenly realised that it wasn't and unfortunately it appeared to be a body lying in the central lane with police and ambulance staff around it.
"Because of the torches being shone by police (I could see) it appeared that the body had been struck by vehicles.
"It was very shocking. It is not a sight I would want anyone to witness.
"My condolences are with the family of the deceased."
Police had appealed for drivers who were on the road at the time of the incident to check their vehicles for signs of a collision and look at dash cam footage.