One person was killed when a lorry hit the central reservation and turned over near to the entrance of Newport Pagnell Services on the M1 on Sunday.
Thames Valley Police were called to the southbound carriageway near the services between junctions 15 and 14 at 4.26pm, to reports that a lorry had turned over.
The lorry driver, a 54-year-old man from Kent, died at the scene.
Two others, who were also in the lorry, suffered minor injuries.
The lorry also collided with a blue Ford Focus car.
Anyone who witnessed the collision or who has any information about the incident can contact PC Neil Stephenson or Sgt Fraser Chamberlain from the Thames Valley and Hampshire Joint Roads Policing Unit on 101.