The victim, whose name wasn’t immediately released, died at the scene, according to police.
Investigators said it did not appear the man was wearing a seat belt.
No one else was in the vehicle.
Police said there weren’t any witnesses to the crash.
Investigators said a passerby came up on the accident scene and called 911.
Greenwich Pike remained closed while the Lexington Police Department’s Collision Reconstruction Unit (CRU) investigated why the driver lost control and crashed.