One person was killed and another was seriously injured in an automobile accident Tuesday afternoon on Interstate 55 south of the 6th Street exit.

According to the state police, a 79-year-old Cottage Hills woman was southbound on the interstate south of milepost 92 when, for unknown reasons, her vehicle swerved from the right lane, across the center lane and into the path of a grain truck, driven by Chase Blankenship of Tovey.

Blankenship's truck hit the car, causing it to spin and roll into the median. The car's driver, whose identity has not been released, was pronounced dead at the scene by the Sangamon County Coroner's Office. Her passenger, Bobby McNealy, 57, of Hillsboro, was taken to Memorial Hospital with serious injuries.

Blankenship, 25, was uninjured in the accident, which occurred around 12:17 p.m. Tuesday.