Police cordoned off the area around the car involved in the fatal accident that occurred July 1, 2024, near City Hall Station on the Seoul subway. (Yonhap)

After a car ran over pedestrians near Seoul City Hall on Monday, killing nine people, a heated debate has erupted over whether the crash was caused by sudden, unintentional acceleration, as the driver claims. While the car driver claims his vehicle “failed to stop” despite “braking,” experts say some evidence suggests otherwise.

Sudden unintended acceleration refers to a phenomenon in which a vehicle accelerates rapidly, regardless of the driver’s intentions. The exact cause of this phenomenon has not yet been determined.

Controlled stop raises doubts about unintended acceleration

Experts say the characteristic features of a vehicle involved in a sudden, unintended acceleration accident are that the vehicle suddenly accelerates and comes to a stop on impact.

For example, in 2011, a driver who killed a 70-year-old woman while driving in Andong, North Gyeongsang Province, was charged with violating the Act on Special Cases Concerning the Adjudication of Traffic Accidents, but was acquitted when it turned out that a vehicle defect (confirmed by sudden, unintentional acceleration) may have been the cause.

In this incident, the driver’s vehicle failed to stop even after colliding with a telephone pole and another car. The vehicle only stopped after the engine made a roaring sound for over a minute.

If we look at the circumstances of Monday’s crash, the car was hurtling toward the sidewalk at terrifying speeds, but unlike vehicles in other crashes with sudden, unintentional acceleration, this one managed to come to a stop slowly.

“While it’s possible that the car experienced sudden acceleration and returned to normal shortly thereafter, this is not a typical phenomenon,” Kim Pill-soo, professor of automotive technology at Daelim University College and chairman of the Automotive Sudden Acceleration Research Society, told Hankyoreh by phone. “Videos showing a driver successfully applying the brakes to stop the car immediately after a crash can be used as evidence that the vehicle was operating normally.”

“When an accident occurs on a short stretch of road, most people will experience memory loss and have no recollection of the event, leading many to believe that the accident was caused by sudden, unintentional acceleration,” Kim added.

However, it is difficult to assess whether the perpetrator of the accident should bear full responsibility based solely on the fragments of information available so far.

“You have to look at how the driver reacted, whether he tried to avoid the collision and what path he took when hitting the victims,” suggested Ha Jong-sun, a lawyer who has defended many victims suspected of causing accidents caused by sudden, unintentional acceleration.

“It is possible that a software reset that would have occurred after a large collision caused the brakes to return to normal after they had failed to function properly due to sudden acceleration,” he added.

Police said they would ask the National Forensic Service to analyse the vehicle’s event recorder (EDR) and other factors to determine whether the incident was a case of sudden, unintentional acceleration.

EDR is a device that records the change in vehicle speed before and after a collision, brake operation and engine speed, providing valuable data needed to determine the cause of an accident.

The Meaning of Explosion and Brake Light Sounds

Another important factor in determining whether this was a case of sudden, unintended acceleration is whether any explosion-like sounds were heard, as these are one of the telltale signs of the phenomenon. Experts also say the roaring sound emitted during such events is something most people have never heard before. Witnesses to Monday’s crash reported hearing a “fuel tank exploding” and “thunder.”

It should also be investigated whether the vehicle’s brake lights illuminated during the collision. Brake lights, which are directly connected to the brake pedal without any other intervening device, are considered the most useful way to indirectly prove accidental acceleration and human error because they illuminate when the pedal is pressed, regardless of whether the car is running or not.

“To confirm the claim that the accident was caused by sudden acceleration, it is necessary to obtain video evidence that proves that the brake lights were on from the beginning to the end of the accident,” said Lee Ho-geun, a professor of automotive engineering at Daeduk University.

Controversy over older drivers

The fact that the driver was almost 60 years old also caused many to blame his age for the accident.

According to the traffic accident analysis system of the Korea National Road Traffic Administration, 20% of all traffic accidents that occurred in 2023 were caused by drivers aged 65 and over.

The overall road traffic fatality rate (number of fatalities per 100 crashes) in crashes involving drivers aged 65 and over over the last 10 years (2014–2023) was also significantly higher than the overall average (1.7), with 2.6 fatalities in this age group.

By Lee Ji-hye, Staff Reporter

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