The trial of a former Edmonton police constable charged with impaired driving began with dramatic testimony from the teenager driving the pickup truck that collided with the officer's BMW.

Robert Wasyliw, 19, testified Monday morning at the trial of Douglas Kurtis Brown in Edmonton provincial court.

Brown is charged with five counts of impaired driving causing bodily harm, five counts of dangerous driving and one count of driving with a blood alcohol level over the legal limit.

Brown, who resigned from the police service in September, was not on duty at the time of the collision.

In his testimony, Wasyliw said he remembered stopping at a red light while he was driving three friends home after a late-night meal at a restaurant.

When the light turned green, Wasyliw drove into the intersection. That's when he was hit, he said.

"I remember waking up with the truck on its side," he told provincial court judge Mike Allen.

The vehicle was on fire, but when he tried to move, Wasyliw realized his arm was pinned under the truck outside the window.

"I started screaming for help," he said. "I remember drips of flame hit me."

Wasyliw then curled up into a ball in a desperate bid for survival.

Just then, the truck turned upright, and a man pulled him out of the window and walked him away from the vehicle.

Thirty seconds later, the truck exploded.

Wasyliw suffered broken bones and burns over much of his body. The three other teens riding in the truck were treated in hospital and released.

The trial is expected to last all week.

With files from Janice Johnston