The plaintiff's appeal is dismissed.

The costs of appeal shall be borne by the plaintiff as the supplementary intervenor.

1. Basic facts

A. The Plaintiff is an insurer who has entered into an automobile insurance contract with respect to D vehicles (hereinafter “Plaintiff vehicles”). The Defendant is a mutual aid business operator who has entered into an automobile mutual aid contract with respect to E bus vehicles (hereinafter “Defendant vehicle”).

B. On September 11, 2019, the Plaintiff’s Intervenor driven the Plaintiff’s vehicle and was driving the two lanes of 259 degrees 3 lanes in Dongdaemun-gu Seoul, Dongdaemun-gu. The Defendant’s vehicle departing from the three-lanes, attempted to change its course into two-lanes, and there was an accident that conflicts between the left rear part of the Defendant’s vehicle and the front part of the Plaintiff’s right side (hereinafter “instant accident”).

C. On November 28, 2019, the Plaintiff paid KRW 446,200,00, after deducting KRW 200,000, for the repair cost of the Plaintiff’s vehicle due to the instant accident.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1 through 5 (including paper numbers, hereinafter the same shall apply), Eul evidence No. 1, and the purport of the whole pleadings

2. Judgment on the plaintiff's right to indemnity

A. In full view of the following circumstances that can be recognized by comprehensively taking account of the above facts admitted as fault ratio and the evidence revealed earlier, the driver of the Defendant vehicle appears to have changed the course in the future of the Plaintiff vehicle despite the possibility of hindering the normal passage of the Plaintiff vehicle, which driven two lanes while changing the course at the time of the instant accident, and on the other hand, even though the Plaintiff’s Intervenor is obligated to drive safely, the Plaintiff’s Intervenor appears to have maintained speed after the first rapid reduction of speed, and thus, the instant accident was caused by the negligence of the Plaintiff vehicle and the Defendant vehicle, in light of the circumstance leading up to the instant accident, the degree of collision, and destruction of the vehicle.

It is reasonable to view that the ratio is 30:70 in light of the above circumstances.

(b) scope of indemnity;