As he mourned his father's smoking-related death in 1995, Rob Hill looked to his former elementary school as a way to honor his dad.

He promised more than 100 fourth-graders over two years at Brookside Elementary in Lake Forest Park $500 each if they stayed tobacco-free until graduation. He called it The Smoke-Free 500 and set up a foundation in his father's name.

He kept his promise. Thursday, more than 30 kids collected checks at an informal ceremony at Third Place Books in Lake Forest Park. He rewarded 20 students last year.

As the graduates ate pizza and cake, Hill, who's in the real-estate business, wrote more than $15,000 worth of personal checks, one by one.

The concept came from Hill's father, Bob Hill, who owned Shoreline's North City Lumber. The elder Hill promised each of his four children a car if they graduated from high school as nonsmokers. Rob Hill and his siblings used that incentive to deflect peer pressure throughout high school. "We'd say, 'Hey, I can't. We're going to get a car if we don't smoke.' "

Graduates said they have done the same.

"People have asked me if I smoked, and I'm like, 'No, and I'm getting paid for it,' " said Erica Delph, who is graduating from Shorecrest High School.

Hill, 45, originally planned to test the students for tobacco products throughout middle and high school. When no one was tested, some kids said they figured it was a hoax. But rumors that there would be tests at Thursday's award ceremony may have kept some kids honest, students said.

Hill said he settled on an honor system when the tests seemed too complicated. Some kids may be lying to get the money, he said, but if so, "that's their problem."

"It brings me back to what my dad used to always say," Hill said. "Ninety-five percent of the people in the world are honest. You can't really worry about the other 5 percent."

Emily Heffter: 206-464-8246 or eheffter@seattletimes.com