A Salt Lake man found dead in the weeds off Interstate 80 on Sunday may have been hit by a car.

Rodney Jackson, 47, may have been dead for several days when he was spotted by a motorist near 2000 West and eastbound I-80, said Utah Highway Patrol trooper Cameron Roden.

Jackson died from blunt force trauma to the back of his head, according to the results of an autopsy released Tuesday. "Something that was consistent with high velocity," Roden said.

Police are investigating the possibility Jackson was hit by a car or clipped by a mirror on a semitrailer. Detectives found skid marks near where the body was found Sunday, but Roden said it was unclear if those were related to Jackson's death.