Four people ran off on foot after a motorway collision that killed a 27-year-old man, police said.
Officers have been searching for the group, who were in a Mercedes, since the incident on the M40 at about 01:15 BST.
It happened on the northbound carriageway at Beaconsfield, Buckinghamshire, and led to a closure being enforced up to the M25 Denham interchange.
Thames Valley Police said a 26-year-old man from the town was arrested on suspicion of causing death by dangerous driving.
He was taken into custody, also being held on suspicion of possessing a bladed article.
The deceased was driving a Volkswagen Golf and his passenger, a man in his 20s, was taken to hospital with serious injuries.
Police said work was ongoing to identify and locate the two men and two women who ran away from the collision scene.
Witnesses reported seeing the Mercedes AMG C250 being driven “erratically” in the moments prior, according to Det Sgt Edward Crofts.
He said the 27-year-old man’s family was being supported by specially trained officers.
“I am appealing to anybody who was driving on that stretch of the M40 in the early hours of this morning and witnessed the collision to please get in touch,” the detective added.
Fire and ambulance services also attended the scene and a diversion was put in place.
Drivers were warned of large delays at the Denham interchange, which is used by motorists wanting to access London Heathrow Airport.
Joining with the M25, it also provides onward journeys to the M1, M4 and M11.
