You are about to turn right at an intersection on an ordinary road (not an expressway). Which describes the correct way to signal with your turn indicator?
A turn signal is started a set distance before the point where you will act and kept on until the action is finished (Article 38(1) of the Road Traffic Act and Annex 2 of its Enforcement Decree). The distance differs between ordinary roads and expressways, and note that the signal is not only for the car behind.
Answer: ②
Explanation
Under Table 2 of the Enforcement Decree (Article 21), the signal for a right turn is given on reaching a point at least 30 meters (100 meters on expressways) before the edge of the intersection. Article 38(1) of the Road Traffic Act requires signaling until the maneuver is finished, so you must not switch it off as soon as you start turning. The signal informs pedestrians and oncoming vehicles as well as those behind, so it is required even with no one following.
Legal basis: 도로교통법 제38조 제1항, 시행령 제21조 별표2