A speeding car T-boned a blue Subaru Forester that was trying to get on the Deerfoot Trail on-ramp, flipping the vehicle onto its side, said witnesses. (Peter Akman/CBC)

Calgary police stunned a fleeing suspected car thief with a Taser after a high-speed crash on Memorial Drive and Deerfoot Trail on Tuesday morning.

Officers in an unmarked police vehicle saw an older-model Chrysler Dynasty weaving in and out of traffic eastbound on the 5th Avenue flyover downtown at about 10:30 a.m. and followed it onto Memorial Drive. They activated the police sirens and lights to pull the car over, but the vehicle sped off, said police spokeswoman Nichole Stewart.

Police, who were at that point on Memorial Drive near St. Georges Drive, then turned off their lights and sirens as it is the force's policy not to initiate a pursuit in high-traffic situations, she said.

According to witnesses, the Chrysler proceeded up on the shoulder at high speed to bypass vehicles stopped at a red light but smashed into a Subaru Forester that was turning onto the Deerfoot Trail on-ramp.

The impact flipped the Subaru onto its side, but a barricade prevented it from falling onto Deerfoot Trail below.

"He hit her on the passenger side. She went up on the meridian, and I thought she was going to bounce right over," said witness Mike Sloane.

Woman in stable condition in hospital

Paul Haynes said he saw the Chrysler speed through the red light, then broadside the Subaru.

"As soon as he hit the vehicle, he got out of his car and started to run," Haynes told CBC News. "He was coming, so I tried to give him a kick and trip him. But by that time, the police had already gotten out and actually attempted to run after him as well."

Stewart said an officer deployed a Taser once, but it was ineffective because the shock didn't penetrate through the suspect's heavy clothing. Sloane said he thought police shocked the suspect a second time before an arrest could be made.

A male suspect was handcuffed to a spine board, before being taken away for medical treatment. (Peter Akman/CBC)

Haynes said it didn't look like police were in active pursuit of the suspect because it was a few minutes before cruisers arrived on scene.

The man, in his 30s, was handcuffed to a spine board before being taken for medical treatment. He was released into police custody on Tuesday afternoon and is facing several charges, including possession of stolen property, said police.

The woman driving the Subaru was unconscious when paramedics arrived, said witnesses. Fire crews used the jaws of life and hydraulic cutters to peel back the roof of the car to reach her, said Jeff Budai, spokesman for the Calgary fire department.

The woman, 39, was taken to hospital with soft-tissue injuries. She's in stable condition, said Stuart Brideaux, spokesman for Calgary Emergency Medical Services.

Police did not learn that the Chrysler had been reported stolen until after the crash, said an update from the force on Tuesday afternoon.

Investigators believe alcohol was a factor in the crash. Police were seen emptying a mini-keg can of beer, which investigators had removed from the Chrysler, onto the road and putting it into an evidence bag.

With files from Peter Akman