NEW GLOUCESTER — A woman was injured Monday night when her sedan and a tractor-trailer collided on the Maine Turnpike, state police said.

Barbara Pierce, 55, of Cape Elizabeth, suffered head injuries in the crash near mile 70 on the turnpike at about 5 p.m., Trooper Fern Cloutier said.

Both vehicles were traveling south when the tractor-trailer, driven by Otis Rogers, of Ruleville, Miss., and Pierce’s vehicle collided, sending the car into the median guardrail, Cloutier said.

The unloaded tractor-trailer also hit the guardrail, then traveled across the the right lane of the turnpike and landed in a ditch, Cloutier said.

Both southbound lanes were closed from 5:15 p.m. to about 6 p.m., while emergency responders treated Pierce, he said.

Pierce was taken to St. Mary’s Regional Medical Center in Lewiston, and was later transported to Maine Medical Center in Portland by ambulance, Cloutier said.

The right lane remained closed until about 8 p.m. as police and others worked to clear the road and free the truck from the gully.

The accident is still under investigation, Cloutier said.