This photo captured from local broadcaster KBS's news coverage shows the car dashing with smoke on Dec. 6 in Gangneung, Gangwon Province. (KBS)

On Dec. 6, a sport-utility vehicle driven by a 68-year-old woman suddenly raced about 600 meters forward for about 30 seconds before falling into an underpass in Gangneung.

The driver’s 12-year-old grandson was killed, while the driver suffered severe injuries.

This week, the family has filed a lawsuit against the car manufacturer, alleging that it was a sudden unintended acceleration due to vehicle defects.

“To prevent similar accidents in the future, the car’s manufacturer should prove what caused the accident,” said the bereaved family, who filed the product liability suit Tuesday with the Chuncheon District Court.

They also called on the National Assembly to push for legislation that requires the adoption of acceleration suppression systems to prevent sudden burst of speed, and automatic emergency braking that activates in case of sudden unintended acceleration.

Police and the National Forensic Service are looking into the fatal crash, testing the model that crashed, and the results are expected to come out as early as mid-January. Since the grandmother was the driver, she has been booked for the investigation on charges of violating the Act on Special Cases Concerning the Settlement of Traffic Accidents.

In a voice recording from the car’s black box that was shown on local television, the driver is heard exclaiming “why isn’t this working?”

The family claims that the SUV, which has Level 2 autonomous driving functions, had defects in its electronic control unit software and the automatic emergency braking as the AEB didn’t work. It also did not have an ASS or a roof that can withstand impacts. Level 2 autonomous driving means the car can drive itself, but requires the driver to monitor it at all times and be ready to step in if needed.

The family said there was a tendency in Korea to blame most accidents from suspected sudden unintended acceleration on driver error.

The fact that the driver tried to avoid colliding with other cars at least twice while her vehicle was racing by itself shows that it was not a case of driver error, the family said. The fact that the car made a roaring noise, spurting out white liquid, is another reason to suspect a vehicle defect, they added.