A 20-year-old University of Colorado student killed in a motorcycle accident Tuesday afternoon was headed home from his summer job at Guiry''s Paint, Wallpaper & Art Supplies in Boulder.

Christopher P. Thrush was an "extremely intelligent" third-year engineering student at CU who loved to ride his motorcycle and knew how to work hard, his family and friends said Wednesday.

"What he knew would just boggle me. Chemistry, global issues - you could ask him almost any question and he could answer it," said Hunter Fahey, one of Thrush''s best friends, who''s spending the summer in Wichita, Kan.

Thrush was staying in Fahey''s Boulder apartment this summer, and the pair planned to live together this fall, said Fahey, 20.

"We were always together," he said.

Fahey said Thrush loved his blue Suzuki Katana, and would leave it home only on freezing days, forcing him to "bum rides."

Boulder police said Thrush was headed south on 30th Street at Shadow Creek Drive at about 3:20 p.m. Tuesday when he collided with a utility trailer being pulled behind a truck. He was taken to Boulder Community Hospital, where he died of blunt force injuries, according to the Boulder County coroner.

Detectives still are investigating the wreck and haven''t ticketed or arrested anyone. According to police records, at least 10 people died in motorcycle accidents last year in Boulder County.

Thrush, who''s been riding since his senior year at George Washington High School in Denver, wasn''t wearing a helmet, his dad said Thursday.

Tom Thrush said his son was a hard worker, having landed his first job at a pharmacy at age 13.

"We told him he could go to Europe last year instead of work, but he wanted to try and contribute to his tuition," Tom Thrush said.

He said his son volunteered at the Dumb Friends League and loved Blue, the family''s border collie.

Father and son spent spring break this year in Arizona''s Havasupai Indian Reservation, backpacking around the Grand Canyon''s southern rim.

"You have to hike 10 miles into the village," Tom Thrush said. "It was his first real backpacking experience, and he was so proud of himself. It was really steep, and he had a big grin on his face."

Even during vacation, though, Thrush thought about his studies and upcoming tests, Tom Thrush said. He said the young man had better than a 3.0 grade-point average and was planning to complete CU''s five-year master''s program in engineering physics.

"He had a good future," Tom Thrush said. "He was an even-tempered, sweet, hard-working kid. He had everything going for him."