Friends and family of two Penn Hills children killed in a New York highway accident will hold a memorial hike in Frick Park tomorrow to raise money for a playground in their names.

Kate Ambrusko, 6, and her brother, Peter, 4, died April 6 when a car driven by their father, Dr. Steven J. Ambrusko, veered off Interstate 90 as he drove from Erie to Buffalo.

Kate was a first-grader at the Environmental Charter School at Frick Park and Peter was scheduled to attend the school in the fall.

Both children loved the school, said their mother, Amy Ambrusko, 34, so she decided to build a playground for them nearby. Divorced from Dr. Ambrusko, Ms. Ambrusko had custody of the children during the week and was devoted to them.

"That night I asked myself, 'What's my purpose?'" she said. "I was a stay-at-home mom and now my kids are gone. I asked my dad and he said, 'You have to find a way to memorialize these children.' So that's what I'm doing."

The memorial hike will raise money for the Kate and Peter Ambrusko Memorial Fund, which will be used to build the playground. The exact location hasn't been determined, but the school is planning an expansion and it will probably be part of that.

"I know it would make them happy and honor their playful spirits!" Ms. Ambrusko wrote on her Facebook page after the children died.

She had been promising to build them a tree house in the last few months and said the playground may include one.

Ms. Ambrusko said family and friends who want to hike can ask others to walk with them or sponsor them by making a donation to the memorial fund.

Hikers are asked to bring the donations with them to the hike, which starts at 9 a.m. at Turtle Park next to the school. Organizers will be selling lemonade, snacks and other items at the hike.

"This event is open to the public," Ms. Ambrusko said on a flier advertising the hike. "We have lives to celebrate and a playground to build!"

Anyone who can't make the hike but still wants to donate can do so at any time, either by dropping off a donation at the school or sending it to the Kate and Peter Ambrusko Memorial Fund at the Environmental Charter School at Frick Park, 829 Milton St., Pittsburgh, PA 15218.

Dr. Ambrusko, a former Children's Hospital doctor practicing in Buffalo, drifted off the highway and plunged down a hillside in remote Chautauqua County, N.Y., after he had picked up the children in Erie from Ms. Ambrusko.

He survived but the children were pronounced dead at the scene.