A motorcyclist was in serious but stable condition Thursday at St. Benedict's Hospital with back injuries suffered in a motorcycle-semitrailer truck collision that killed his companion.

A Utah Highway Patrol dispatcher said Joseph Janak, 25, Riverdale, Weber County, was westbound on 21st Street when the semitrailer truck, driven by Robert Clay Emerson, 28, Babb, Mont., pulled onto an I-15 off-ramp at 1150 W. 21st Street in the Wilson Lane area of Ogden.Emerson, who had stopped his loaded rig on the side of the road, did not see the motorcyclist, the UHP said.

Dead at the scene of the 11:52 p.m. Wednesday crash was Sherry Davis, 22, North Ogden, a motorcycle passenger who suffered massive head injuries.