1. The defendant's appeal is dismissed.

2. The costs incurred by the intervention shall be borne by the Intervenor.

1. Basic facts

A. The Plaintiff is an insurer who has entered into an automobile insurance contract with D and E (hereinafter “Plaintiff”) and the Defendant is the insurer who has entered into an automobile insurance contract with F vehicle (hereinafter “Defendant vehicle”).

B. On December 18, 2016, around 14:20, at the time of the Namnam City, the Plaintiff’s vehicle shocked the Defendant’s vehicle as soon as the vehicle stops rapidly due to the sudden stop of the vehicle and the front of the Defendant’s vehicle stops on the front of the vehicle (hereinafter “instant accident”). On December 18, 2016, the Plaintiff’s vehicle shocked the Defendant vehicle (hereinafter “instant accident”).

C. On December 27, 2016, the Plaintiff paid insurance proceeds of KRW 1,762,200 at 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, Eul evidence Nos. 1 and 2 (including paper numbers) and the purport of the whole pleadings

2. The assertion and judgment

A. The Plaintiff’s assertion that the instant accident occurred due to the overall negligence of the Defendant, which was immediately stopped after the rapid change of the lane in the tunnel where the change of the lane is prohibited, while driving along the lane marked with the subsequent vehicle while maintaining the distance from the vehicle at the time of the change of the lane. Therefore, the Defendant, the insurer of the Defendant vehicle, is obliged to pay the Plaintiff the insurance proceeds paid by the Plaintiff and the delay damages therefor.

B. (1) According to the main sentence of Article 14(5) of the Road Traffic Act and Article 8 [Attachment 6] of the Enforcement Rule of the same Act, drivers of motor vehicles and riders of horses shall not change the course of motor vehicles and riders of horses in places where safety signs are installed and it is particularly prohibited from changing the course (where a white light is installed), while Article 19(3) of the same Act intends to change the course of all drivers of motor vehicles.