A woman died and three others were injured Sunday when their westbound car slid and rolled off I-80 in western Salt Lake County.

Nicole L. Ginnett, 19, Tooele, was driving the car and was ejected during the crash. She died at the scene.

Tiffany N. Naill, 22, also of Tooele, was also not seat-belted. Naill, who is pregnant, was taken by medical helicopter to LDS Hospital, said Department of Public Safety spokesman Cameron Roden.

Laurence D. Miles, 22, of Stockton, who was seatbelted and Joshua D. Stickler, 20, Bountiful, who was not seatbelted, were taken by ambulance to University Hospital.

Police were continuing to investigate the accident Sunday night but believe the crash was caused by bad weather and excessive speed.