Police want to hear from members of the public who may have witnessed the fatal collision on the A40 Western Avenue, in Denham in the early hours of Tuesday morning.
At around 3am a white Skoda Octavia, travelling eastbound on the M40 where it merges into the A40, collided with a heavy goods vehicle which was parked in a lay-by, Thames Valley Police reported.
The police statement read: “The driver of Skoda, a man in thirties who was the single occupant of the vehicle, died at the scene.
"The driver of the lorry was uninjured. The road was closed in the area while emergency services attended the scene.”
PC Julia Stroud, from the Serious Collision Investigation Unit, said: “The cause of the collision is under investigation and we would like to speak to anyone who saw the collision or who saw the Skoda travelling prior to the incident.
“If anyone has any information please contact police to speak to the Serious Collision Investigation Unit.”
One lane was closed on the A40 eastbound towards central London causing heavy traffic jams in the area.
Anyone with any information about the incident should contact the 24-hour Thames Valley Police enquiry centre on 101.
If you don’t want to speak directly to the police, you can contact the independent charity Crimestoppers anonymously on 0800 555 111 No personal details are taken, information is not traced or recorded and you will not go to court.