Two people have been killed in separate Utah motorcycle accidents, Utah Highway Patrol officials said Thursday.

Killed:Sherry R. Davis, 22, 2510 N. Mountain Road, Ogden.

James R. Walker, 26, Moab.

Davis, a passenger on a motorcycle, was killed late Wednesday in Ogden when the cycle slammed into the side of a semitrailer truck. The driver of the motorcycle, Joseph A. Janak, 25, 4627 S. 1150 West, Ogden, is in critical condition at St. Benedict's Hospital, Ogden.

UHP reported the truck, driven by Robert C. Emerson, Babb, Mont., pulled off I-15 at the 21st South exit in Ogden about 11:50 p.m. Wednesday. After halting at the stop sign at 21st South, the truck pulled into the intersection, the UHP reported. The cycle, westbound on 21st South, struck the side of the truck.

The UHP said Walker died Tuesday night when the motorcycle he was driving collided head on with a car that had crossed the center line on U-191. Walker was dead at the scene of the 11:20 p.m. crash.

Trooper Richard Haycock said a car driven by Scott Steven Dahlgren, 28, Provo, was traveling south when it crossed the center line into the northbound lanes and struck Walker. Dahlgren was uninjured. The accident is still being investigated.