A man was killed and a woman was seriously injured in an accident on Interstate 78 in Warren Co., N.J., officials said.

The accident happened around 6:20 am. Friday when a car was hit by a tractor trailer  in the eastbound lanes of I-78 in Greenwich Township, state police said.

A man was killed, but has not been identified.

A woman was taken to St. Luke's Hospital in Fountain Hill, Lehigh Co., with serious injuries. Both were riding in a Ford Explorer, according to police.

Police said the Explorer was traveling eastbound on I-78 near milepost 6 when for some unknown reason it left the road and hit a guardrail in the center median. The SUV then returned to the road and was hit by a tractor trailer.

Police said they're not sure whether the man or woman was driving the SUV, but both were ejected from the vehicle.

Police closed the right hand lane to traffic for several hours during the investigation, and traffic was backed up for miles.