1. The plaintiff's appeal and the defendant's incidental appeal are all dismissed.

2. The costs of appeal and the incidental costs thereof shall be individually considered.

1. Facts of recognition;

A. The Plaintiff is an insurer who has concluded a motor vehicle insurance contract with D (hereinafter “Defendant”) with respect to the vehicle C (hereinafter “Plaintiff”).

B. On July 10, 2019: (a) around 15:57, Seongdong-gu Seoul Metropolitan Government changed the lane from the three-lane to the two-lane while the Defendant’s vehicle driving along the three-lanes in Sungdong-dong 1, Sungdong-gu, to the two-lanes, the left side of the Plaintiff’s vehicle changed from the three-lane to the two-lanes.

(hereinafter referred to as “instant accident”). C.

On August 19, 2019, the Plaintiff paid KRW 1,433,00,00 as insurance money, excluding KRW 200,000,00 for the repair cost of the Plaintiff’s vehicle due to the instant accident.

[Ground of recognition] Facts without dispute, Gap evidence 1, 2, 5 through 7, Eul evidence 1 to 3 (including paper numbers) and the purport of the whole pleadings

2. The Plaintiff’s assertion that the instant accident occurred due to the rapid change of the Defendant’s vehicle lane during the given body. Therefore, there is no negligence on the Plaintiff’s vehicle, and the Defendant is liable to pay KRW 1,633,000 to the Plaintiff as well as damages for delay.

3. The following circumstances acknowledged prior to the determination, namely, the driver of any motor vehicle, who intends to change the course of the motor vehicle, are not allowed to change the course when it is likely to impede the normal flow of another motor vehicle running in the direction of the change. The accident in this case occurred while the motor vehicle is changing the lane into the two-lane. ② The driver of the motor vehicle in this case was in need of predicting the existence of the motor vehicle driving in the undeveloped lane before the change of the lane and identifying the route of the motor vehicle; ③ although the motor vehicle in this case entered the two-lanes, it was not completely changed from the three-lanes to the two-lanes, and the driver of the motor vehicle in this case was also a driver of the motor vehicle in front of the motor vehicle in this case.