Sgt. Stephen Jones, a state police spokesman, said the crash occurred around 1:15 a.m. on eastbound Route 78 in the Somerset County community of Bedminster.
Jones said 45-year-old Nicole Widener and 56-year-old Paul Shelly, both of Stewartsville, Pa., were riding on a motorcycle that Shelly was driving when it was struck by another motorcycle driven by 36-year-old Maurice Smith of Patchogue, N.Y.
Shelly was riding in the center lane of the highway when Smith passed them at a "higher rate of speed," and his motorcycle made contact with the rear wheel of Shelly's motorcycle, Jones said.
Widener was thrown into the roadway, where she was run over and killed by a car that left the scene and had not been located as of Sunday night. Shelly ended up on the side of the road and was taken to Morristown Memorial Hospital, where he remained in critical condition Sunday night with leg and other injuries.
Smith sustained several cuts and bruises and was treated at the hospital before being taken into custody.