A man has been arrested on suspicion of murder after a 32-year-old woman's body was found on the M20.
A huge stretch of the motorway was closed London-bound for almost 24 hours following the discovery by Kent Police on Tuesday.
Officers were called to the carriageway between junctions 9 and 10 at Ashford where the person was pronounced dead at the scene just after 6pm.
Detectives appealed for the driver of a silver Nissan Quashqai to come forward.
A man handed himself in at a police station on Wednesday and was arrested on suspicion of murder, Kent Police revealed on Thursday.
He remains in custody.
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 as a diversion was put in place.
The road and the exit slip road reopened just before 3pm 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 are still appealing for drivers who were on the road at the time to check their vehicles for signs of a collision, and for anyone with dash cam footage or who saw a silver Nissan Qashqai at the time of the incident to come forward.
