The Tennessee Highway Patrol responded to a fatal accident in Robertson County where a man and woman were killed. The accident, involving a tractor trailer and passenger vehicle, occurred on State Highway 49 near the Wilks Road intersection.Authorities reported Teresa Jackson, 59, and 36-year-old Jason Jackson was traveling northbound on the roadway when their vehicle crossed the center line and struck a tractor trailer head-on. It remains unclear why the 59-year-old woman crossed over into the oncoming lane of traffic. A second passenger inside the vehicle, identified as 82-year-old Jean Ray, also sustained injuries. Ray's condition was not immediately released. The driver of the tractor trailer, Tommy Johnston, was not injured. The investigation is ongoing.