State Police are investigating the cause of a one-car accident at Route 125 and Route 28 that left an elderly man in serious condition Monday afternoon.

According to State Trooper Kenneth Gaetz, police first reported the accident at 1:55 p.m on Monday.

Gaetz said that North Andover resident James Sheridan was traveling in his 2011 Ford Taurus on Route 125 when he left the roadway, for unknown reasons, and directly hit the concrete bridge support for one of the overpasses at the Route 125 and Route 28 interchange in Andover.

Andover Fire and Rescue responded with extrication tools and had to use the Jaws of Life to get Sheridan from the vehicle.

Traffic on both Route 125 north and south were stopped to allow a medical helicopter to land on Route 125 to transport Sheridan to Beth Israel Hospital in Boston.

Gaetz said Sheridan was in serious condition, as of the most recent update. 

The cause and manner of the accident is still under investigation by State Police Trooper Daniel O'Brien.