Debra Burnfield knows what her son, Nathan, was thinking when he stopped to clear a tire from Interstate 70 outside Bentleyville last week. He was thinking, she said, about the innocent people who might get hurt if he didn't stop.

"Nathan gave himself to save other people, and that's why I'm so proud of him," said Mrs. Burnfield, her voice cracking and tears filling her eyes as she sat next to her son's casket at a funeral home in Washington, Pa., yesterday.

"He thought someone was going to get killed and he knew God wanted him to help."

Nathaniel M. Burnfield, a South Strabane police officer, was killed after he and two other officers stopped to remove tires left in the road by a disabled UPS truck, according to the state police. The officers were returning from a training session and were off-duty at the time.

The driver of a dump trunk swerved to avoid the officers' SUV, which was parked on the highway shoulder with its emergency lights flashing, hit Officer Burnfield as he was leaving the highway with the tire, and then crashed into the UPS truck.

Officer Burnfield, 27, and the dump truck driver, 44-year-old Ronald Kennedy of Connellsville, died at the scene.

When he died, Officer Burnfield had just finished his final class before applying to the county SWAT team, which was his dream, said Mrs. Burnfield. Officer Burnfield, a graduate of Canon-McMillan High School and of Indiana University of Pennsylvania, worked part time as a police officer in Donora, East Washington and South Strabane.

The Burnfield family plans to establish an athletic scholarship in Nathan Burnfield's honor for Canon-McMillan graduates who plan to study criminal justice. Donations can be made to Canon-McMillan Senior High School at 314 Elm Street Extension, Canonsburg, PA 15317.

In 2002, Officer Burnfield was hired for a full-time position in South Strabane but continued pulling some shifts in East Washington and until last year, in Donora, family members said. He also volunteered at the Canton Volunteer Fire Department, where his older brother, Derrick, volunteers as well, and worked as an arson investigator for South Strabane police.

Officer Burnfield loved his job, his mother said, and often worked double and triple shifts when asked. He also taught fire safety classes at schools. Trying for the SWAT team was another way of pushing himself.

"Nathan always liked the adrenaline," she said. "Being a fireman, he was the first in and the last out. He wasn't afraid of the challenge."

Her son lived at home while saving money to pay cash for a house when he made the department's top pay grade in two more years, according to Mrs. Burnfield. Some of his friends teased him about living at home -- a few even called him "momma's boy" -- but he answered them by saying that he took care of his mom, not the other way around, she said.

Her son was a great cook, and often prepared memorable meals for the family, Mrs. Burnfield said. And they always could count on him to help with repairs or other work on the house -- unless he was hunting for deer or bear, a passion he shared with his maternal grandfather, retired Washington Police Chief Paul Kosey.

Her son, she said, was very close to his family, especially his grandfather, his brothers, Derrick and Ron, and his father, Rick -- even though Nathan was a devoted University of Michigan fan and his dad cheered only for Penn State University.

Mrs. Burnfield said she wants people to remember her son for his smile and his compassion, and to take time to appreciate their children while they can.

"Just hug your children, love them," she said. "You never know when they're not going to come home."