STORY CITY — An Ames woman died instantly Friday morning when her car rear-ended a field cultivator pulled by a tractor along the border of Boone County and Story County.

Carol Lawson, 50, 1409 Indiana Ave., was traveling north along Y Avenue about five miles southwest of Story City just before 9 a.m. and apparently didn’t see the slow-moving tractor, said Capt. Gary Foster of the Story County Sheriff’s Office.

“I didn’t notice anything until I got stopped,” said Paul E. Jensen, 547 Y Ave. in rural Ames, who was driving the tractor and pulling a wide chisel plow to a field just northeast of the accident site. “I turned around and saw the car beneath me.”

Jensen said he got out of the tractor and went to the mid-size silver Chrysler, which had continued its travel until it was underneath the plow. The passenger compartment and engine were crushed, and the wreck left skid marks and a debris field of chisels from the plow and metal bits over about 70 feet of roadway.

“Looking at her, I assumed she was dead,” Jensen said. “I was interested in getting a hold of 911 because I couldn’t have gotten her out anyway.”

Jensen and neighbors watched idly for about an hour while firefighters and police officials worked to extricate the woman from her vehicle. She was removed at 10:05 a.m.

“I heard the sound from inside the house,” said Phil Wirth, 13598 500th Ave. in rural Story City. The accident occurred just outside Wirth’s home. “I thought something fell off the house.”

Friday morning was sunny and the accident occurred on a flat, straight length of road that Jensen and Wirth both said is frequented by farm equipment in the spring and fall. Jensen said he was moving about 19 mph when he felt the tractor shudder and thought his plow had dropped to the road.

Foster said he sees farm-related roadway accidents about once a year, usually during planting and harvesting seasons.

“We hope that people will drive carefully and take a little extra time to get to their destination when they’re traveling on these farm roads,” he said.

Jensen lives 2 miles south of the accident site and had almost reached his field.

“If I’d done chores five minutes faster or taken five minutes more to do them, I bet it’d never happened,” he said.