The road was closed for hours on Friday.
A black VW Touran left a rural road which links the Oxford Road and the village of Sunningwell on Friday morning.
Police, paramedics, an air ambulance and the fire service were called but sadly, the driver of the car, a 71-year-old man, died at the scene.
Hisv next of kin have been informed
The road was closed until 1pm while police carried out an investigation.
Officers are now appealing for witnesses.
Investigating officer PC Peter Billingham, of the Roads Policing Unit at Abingdon police station, said: "Our thoughts are with his family at this difficult time. They are receiving support from a family liaison officer.
"We are investigating the circumstances of the incident and are appealing for witnesses to call the Thames Valley Police non-emergency number, 101, quoting reference 43180043480."