[News Terms] Sudden Acceleration Reenactment Test Results Raise Questions About 'Accident Data Recorder' Reliability?

Suspected Sudden Acceleration Accident in Lee Do-hyun's Death Vehicle, Doubts Raised Over EDR Reliability
Discrepancy with National Forensic Service Analysis "Proves Grandmother Did Not Misoperate Pedal" Claim

In December 2022, regarding the suspected sudden unintended acceleration accident involving Lee Dohyun (aged 12 at the time of death), the first domestic reenactment test conducted on the accident site road yielded results from a detailed analysis by a court-appointed expert that support the claim that "Dohyun's grandmother did not press the accelerator pedal."

This is also connected to the loss of trust in the 'Event Data Recorder (EDR),' drawing attention to how it might affect future court disputes.

In Gangneung, Gangwon Province, a "re-enactment test" to determine whether the sudden unintended acceleration of the vehicle, suspected in the accident that caused the death of Lee Dohyun (12 years old at the time of death) in December 2022, was due to a vehicle defect was conducted on the afternoon of the 19th on Hoesan-ro, Gangneung City. Dohyun's father, Lee Sanghoon, is watching the re-enactment test.
[Photo by Yonhap News]

The 'Event Data Recorder (EDR)' is a device that stores vehicle operation information for a certain period before and after a car accident and allows the stored information to be reviewed. It is installed in the Airbag Control Unit (ACU), which controls occupant protection restraint devices such as airbags and seat belts, and safety devices like the pre-tensioner that compensates for seat belt shortcomings.

EDR recorded information can confirm data such as vehicle speed, engine revolutions per minute (rpm), throttle opening percentage (%), brake pedal operation status (on/off), accelerator pedal position (%), ABS (Anti-lock Brake System) activation status, ESC (Electronic Stability Control) activation status, and steering wheel angle (degrees) up to 5 seconds before an event triggered by a physical impact on the vehicle. Depending on the vehicle model or manufacturer, more detailed information may also be stored.

The Dohyun family, who are engaged in a lawsuit against the vehicle manufacturer KG Mobility seeking approximately 760 million KRW in damages, disclosed the expert analysis results of the official reenactment test conducted on the 19th of last month on the 27th.

According to the expert results revealed by Dohyun's family, contrary to the manufacturer's claims, the 'shift pattern' was different, and compared to the National Forensic Service's analysis that found no vehicle defects, the 'driving data' was significantly different. The accident data recorder (EDR) records indicating full acceleration were consistent with the results of pressing the accelerator fully, which showed a much greater 'speed change.'

Based on these results, Dohyun's family emphasized, "It has been proven that the grandmother did not misoperate the pedal, and since there was no pedal misoperation, the sudden unintended acceleration was due to a vehicle defect."

The expert analysis showed that, contrary to the manufacturer's claims, the shift pattern did not match the figures obtained during this actual driving test. The difference was especially pronounced during the reenactment test assuming the moment when the sudden acceleration occurred and the Morning passenger car was struck.

When rewinding to just before the Morning collision, with the shift lever set to Drive (D) at a speed of 40 km/h and the accelerator fully pressed for 2 to 3 seconds, the actual speed increased from 40 km/h to 73 km/h, RPM rose from 3000 to 6000, and the gear shifted from 4th to 2nd to 3rd. This is completely different from the National Forensic Service's analysis, which stated that with the gear in neutral (N), speed and RPM remained steady at 40 km/h and 6200?6400 respectively.

In Gangneung, Gangwon Province, a "re-enactment test" to determine whether the sudden unintended acceleration was caused by a vehicle defect in the suspected sudden acceleration accident involving Lee Dohyun (12 years old at the time of death) in December 2022 was conducted on the afternoon of the 19th on Hoesan-ro, Gangneung City. Cameras and transmission diagnostic devices are being installed on a '2018 Tivoli Air' vehicle, the same model as the accident vehicle.
[Photo by Yonhap News]

Dohyun's family argued that the National Forensic Service's analysis that "the driver operated the shift lever from D to N just before the loud noise and from N to D just before the collision" is entirely incorrect, as previous acoustic analysis expert reports confirmed "no shift lever operation." If the grandmother indeed drove with the gear in D, the National Forensic Service's analysis is completely wrong. The expert stated, "Considering the accelerator pedal and transmission driving patterns, it is unlikely that the shift gear pattern described in the National Forensic Service's report would occur when driving with full acceleration."

Additionally, although the EDR recorded that the grandmother fully pressed the accelerator pedal during the last 5 seconds before the accident, the speed increased by only 6 km/h from 110 km/h to 116 km/h, and it took as long as 24 seconds to reach 116 km/h from 40 km/h after the Morning collision, which was attributed to the grandmother pressing the brake.

This is also linked to the loss of trust in the EDR that Dohyun's family has consistently claimed. In the black box footage from the accident, the grandmother can be heard exclaiming, "Why isn't this working?" indirectly indicating that the brakes were not functioning.

Dohyun's family and the manufacturer will continue their legal battle at the Chuncheon District Court Gangneung Branch on the 18th of next month, where they are expected to fiercely contest the results of this reenactment test. Furthermore, since Dohyun's family decided to conduct their own reenactment test of the 'Automatic Emergency Braking (AEB)' function without officially requesting an expert examination from the court, disputes over the evidentiary value of that test are also anticipated.