Police were contacted at around 11pm on Sunday, July 9, following a single vehicle road traffic collision on the A30 at Innis Downs involving a Volkswagen Golf.
A Devon and Cornwall Police spokesperson said: "Local response officers as well as officers from the roads policing team attended the scene and assisted with first aid.
"Despite the best efforts of the emergency services, a 34-year-old man from the Hampshire area was declared deceased at the scene. His next of kin have been informed."
The road was closed for around six hours whilst a forensic collision examination was completed.
Any witnesses or anyone in the area at the time with dashcam footage that may assist the enquiry are asked to contact Devon and Cornwall police on 101 quoting log number 1005 of 9 July 2023.