Edward C. Kasten, 49, was pronounced dead at 1:28 p.m. at the scene by South Bridge emergency medical services personnel.
A spokesman for the Allegheny County Coroners Office said an autopsy will be performed today to determine the cause of death.
According to state police, the 1:21 p.m. accident occurred when Kasten's vehicle left the road and struck the left guardrail. The vehicle rolled over, landing on the left side.
Police said the vehicle continued rolling forward, ejecting Kasten. The vehicle landed in an upright position.