The man accused of running down and killing Silas O'Brien with his truck testified Monday that he made mistakes on the night of the crash, but had no idea anyone was dead.

Brent Parent is on trial for charges including criminal negligence and dangerous driving causing death in the March 13, 2008 incident that left 21-year-old O'Brien dead on the side of a Langley road.

In B.C. Supreme Court, Parent testified that he was driving home along 16th Avenue on the night of the collision when he noticed headlights coming up fast behind him.

He said he started pressing on the brakes of his Ford F350 pickup truck to get the other vehicle to stop.

"It was stupid and childish," Parent told the court.

When the other vehicle started to pass him, Parent said that he sped up, something he called another stupid move.

At that point, he testified that he heard a rubbing noise, indicating that the vehicles had made contact, and saw the other truck go into the ditch.

During cross-examination, Parent was asked why he didn't stop right away.

"I should have, but I didn't," he testified.

He rejected prosecutors' suggestions that he hit the other vehicle up to three times and forced it off the road.

Parent testified that when he returned to the scene a few minutes later, he saw three people at the side of the road, and two of them approached his truck as he got closer.

O'Brien's friends Luke Stephen and Sam Dooley testified earlier in the trial that they were waving their arms and yelling at the truck to stop.

Parent told the court that he was looking at the two men when he heard a bang. He said he thought someone had kicked his truck or thrown something at it, and he decided to leave.

He began to choke up on the stand as he said that it wasn't until hours later when he saw a news report that he learned O'Brien had been struck and killed.

He said he took the snowmobile rack off his truck so it couldn't be identified, because he wanted time to think and get legal advice.

Parent and his brother were stopped by police later the same day, but it took nearly a year before Parent was charged in connection to O'Brien's death.

Outside the court, Parent told reporters that his time on the stand was, "hard -- very hard."

O'Brien's mother Michelle described Parent as "a sad man."

Vancouver city councillor Geoff Meggs, O'Brien's uncle by marriage, also attended Monday's proceedings.

"It's a very sad day," Meggs said. "It's a wonderful family and he was taken from them, so it's quite difficult to listen to the testimony."

Crown and defence lawyers are expected to make their final submissions in Parent's trial in early November.

With a report from CTV British Columbia's Maria Weisgarber