A former Edmonton police constable is on trial this week charged with impaired driving and dangerous driving causing bodily harm.

On May 11th, Douglas Kurtis Brown, 29, was out with friends driving his 7 series BMW southbound on 66 St. when he allegedly drove through a red light and collided with a late model Ford pickup truck that was making a left-hand turn from Whitemud Drive onto 66 St. Sunday at about 2:15 a.m.

The impact of the collision smashed the driver's side of the truck and caused it to roll onto its side.

The truck caught on fire with driver, 18-year-old Robert Wasyliw, pinned underneath. All three passengers, two males and one female, managed to get out of the truck.

Wasyliw testified in court Monday describing his pain as his arm was trapped under the truck after the impact.

"I just started screaming for help hitting the roof. By that time the fire had spread to the passenger's side. All I remember was drips of flame hitting me. I huddled up to protect myself from the flames," he told the court.

Passers by stopped to help and pushed the truck upright so that it was sitting on its wheels again. They pulled the driver out from underneath the truck before it was fully engulfed in flames.

Albert Howe witnessed the crash and also testified Monday.

Howe said he was going southbound on 75th Street approaching the Whitemud, when  Brown's BMW came up behind his car. He claimed the BMW was going about 100 kilometres an hour when it passed his vehicle and crashed into the truck.

"As I approached the light was red. I saw reflecting lights in my rear view mirror. He came up and went through the intersection," Howe told the court.

Candace Henriques, a nursing student, was a passer-by who attempted  to help in any way she could.

She told the court she had a conversation with Brown, and he told her he had called 911.

"He was the one who told me he had called 911. He was just pacing back and forth," she said. "I remember thinking he was acting like he'd done something wrong."

Wasyliw was rushed to hospital with a broken collar bone and serious burns to his back and arm.

He recovered in the Intensive Care Unit at the University of Alberta Hospital.

There were three passengers in Brown's car, two women and one man, ranging from 19 to 29-years-old. They were all able to walk away from the collision without any injuries.

The court is expected to hear from more witnesses this week and the trial is slated to continue for five days.

Brown has since resigned as a constable from the Edmonton Police Service.

With files from Erin Isfeld