Idaho State Police investigated a two-vehicle crash southbound Interstate 15 at milepost 168, near Dubois Thursday around 5:05 a.m.
ISP reports Joseph Melfi, 36, of Taylor, Ut was driving a 2000 Kenworth semi pulling double trailers, and Lindy Larson, 45, of Lodi, CA was driving a 2003 Chevrolet Suburban pulling a horse trailer.
Melfi rear-ended Larson and went off the right shoulder and rolled. Larson also went off the right shoulder.
ISP said Melfi was not wearing a seatbelt at the time of the crash, and Larson was wearing a seatbelt.
One lane of travel is still blocked for the investigation of the crash.