VALLEY FORGE, Pa. (CBS) – A tractor trailer that was traveling from the Valley Forge interchange to the Pennsylvania Turnpike overturned Friday morning and created a traffic nightmare for over four hours Friday morning.

The accident happened at about 7:20 a.m. in Valley Forge.

It appears the driver was traveling in the on-ramp towards the Pennsylvania Turnpike when he somehow lost control, flipped over and landed on the concrete barrier separating the westbound on and off-ramps for the Turnpike.

The driver was trapped in the cab for nearly two hours before rescue crews were able to free him. He was flown to the Hospital of the University of Pennsylvania for treatment of non-life threatening injuries.

Both the on-ramp and off-ramp were closed for four hours before they were re-opened at about 11:30 a.m.

The accident remains under investigation.