A pedestrian in downtown San Francisco was found critically injured and trapped underneath a driverless car Monday night. But it was not the first car to strike the victim.

The driverless vehicle was operated by Cruise, a San Francisco-based self-driving car company and subsidiary of General Motors (GM). Video shown to CNN by Cruise shows the autonomous vehicle was a secondary car in the collision and the pedestrian was crossing the intersection when cars had the right of way.

The video has not been publicly released by Cruise with the company citing the ongoing investigation by San Francisco authorities.

San Francisco Fire Department spokesperson Justin Schorr told CNN early Tuesday that the victim has multiple life-threatening injuries.

“A human-driven vehicle struck a pedestrian while travelling in the lane immediately to the left of a Cruise AV,” said Cruise spokesperson Navideh Forghani in a statement to CNN. “The initial impact was severe and launched the pedestrian directly in front of the AV. The AV then braked aggressively to minimize the impact.”

Forghani says the driver of the other vehicle fled the scene.

The video from the autonomous vehicle showed the front and left side camera angles and started when the AV is stopped at a red light, to the right of the suspect car, at the intersection of 5th and Market Streets. The light turned green and both cars proceeded through the intersection and approached a crosswalk. As the two cars approached the crosswalk, a woman was seen walking across the crosswalk despite the oncoming cars. She unsuccessfully tried to beat the manned green vehicle to the left side of the AV.

When the pedestrian was hit by the green car, she landed on the hood of the car, flipped over the roof and rolled off the right side of the car. She slammed onto the pavement and landed right in front of the AV. The AV brakes engaged as soon as she hit the pavement and then stopped on top of her. She landed parallel to the lanes. It's unclear from the video if the front tires ran over her or if she just ended up underneath the car.

A representative for Cruise said San Francisco Police asked the company to not move the AV while the car was on top of the woman.

Schorr said representatives of the company responded to the scene of the accident “very swiftly” and have been cooperating with investigators.

“There was no driver and no passenger in the car to be able to tell us what happened,” Schorr said. But he added that Cruise cars have their own cameras and collect a variety of telemetric data which may help in the investigation of the accident. “It's a very unique type of response for San Francisco,” he said.

The pedestrian, who has not been named, was being treated at San Francisco General Hospital for what a Fire Department spokesperson described as “multiple life-threatening injuries.” The San Francisco Police Department is investigating the accident but has not yet commented on the cause.

“Our heartfelt concern and focus is the wellbeing of the person who was injured and we are actively working with police to help identify the responsible driver,” the Cruise spokesperson said.

Firefighters used a tool they call the “jaws of life” to lift the vehicle off the victim before removing her from underneath it.

Lt. Mariano Elias of the San Francisco Fire Department told CNN this was the first incident “where we have a serious bodily injury from an autonomous vehicle.”

CONTROVERSIAL DRIVERLESS CARS

Cruise has been the subject of controversy in San Francisco after California regulators last month approved robotaxi companies to operate their driverless cars 24/7 throughout the city.

The company's self-driving cars have been blamed for massive traffic jams and multiple collisions, including one that involved a fire truck. One of its driverless taxis drove into a construction area and .

The San Francisco Fire Department said they have tracked 83 incidents this year involving autonomous vehicles. That figure represents the number of times vehicles have blocked or impeded the department from conducting their operations, rather than incidents of an autonomous vehicle injuring someone.

Cruise agreed to the California DMV's request to reduce its fleet by 50% while it takes corrective action.

The recent events underscore the challenges of creating safe, fully driverless passenger vehicles.

General Motors acquired Cruise Automation in 2016 for US$1 billion, solidifying its place in the autonomous vehicles race, but many companies have since scaled back, or abandoned their driverless car ambitions. The endeavour has proven costly, and mastering all situations that humans might face behind the wheel is difficult and time-consuming.

Ridesharing giants Uber and Lyft have both sold autonomous vehicle units in recent years. Even Tesla CEO Elon Musk, who has been optimistic about autonomous vehicle technology, has yet to fully deliver on his promise.

But advocates say driverless cars remain safer than human-operated vehicles.