Traffic accidents Friday and Saturday left four people dead and one seriously injured, according to law enforcement officers.

KILLED:Tonya Dickson, 17, Morgan.

Wendy Wayment, 19, Uintah, Weber County.

Martha L. Mason, 45, 634 S. 12th East.

Benjamin Browning, 3, 1920 W. 13035 South.

Browning and his twin sister were in the back of their father's pickup truck, traveling east on 13035 South about one block from their home at 7 p.m. Friday. The victim apparently stood up and ran around the truck bed and then fell out the left side of the truck, said a Salt Lake County sheriff's deputy. The boy was pronounced dead at Primary Children's Medical Center.

Dickson, Wayment and Jodi Clydesdale, 18, Peterson, Morgan County, were westbound on I-84 when their Toyota left the road about 11 p.m. Friday. It traveled about 200 feet before striking a boulder, ejecting the three passengers. Dickson and Wayment were pronounced dead at the scene, according to the Utah Highway Patrol. Clydesdale was taken to McKay-Dee Hospital in Ogden where she was in stable condition Saturday afternoon, a nursing supervisor said.

Mason and another woman were riding bicycles northbound on Redwood Road about 17th North about 9:30 a.m. Saturday when a southbound pickup truck veered east and struck Mason, killing her instantly, Salt Lake Police Lt. Norm Thompson said.

The truck traveled into a nearby field, coming to a stop against a dirt abutment. The driver was treated for minor injuries at University Hospital. The case is under investigation, Thompson said.