MOSES LAKE — A 54-year-old woman died accidentally Thursday when the four-wheel ATV she was driving was struck by a pickup truck driving along Hiawatha Road, less than a mile north of Interstate 90, authorities said.

Bella V. Ayupan, of Moses Lake, who was driving the 2004 Polaris ATV four-wheeler, was pronounced dead at the scene by Grant County Coroner Jerry Jasman. An autopsy was scheduled for today by Jasman to confirm the cause of death.

The Grant County Sheriff's Office reported Ayupan was traveling northbound in the 1600 block of Hiawatha Road, moving along the asphalt roadway and dirt shoulder, when she began turning left into the center of the roadway, attempting to move toward her driveway. She was immediately struck from behind by a northbound 1998 Toyota pickup truck, which was attempting to pass the ATV.

Ayupan was not wearing a helmet while riding the ATV and appeared to die of massive head injury, Chief Deputy Courtney Conklin said.

"It doesn't look like speed was a factor," he said. Alcohol also doesn't appear to be a factor.

The pickup truck driver, Kyle Christie, 22, of Wenatchee, told responding deputies he was traveling about 45 miles per hour. Christie, who was the only accident witness, called emergency personnel immediately after the collision, about 11 a.m.

He was on-duty for a Wenatchee-based delivery service at the time of the accident.

His pickup truck was towed from the scene, but the extent of damage was unknown, Conklin said. Ayupan's ATV was totaled.

The sheriff's office, Conklin said, is continuing its accident investigation.