What does the following safety sign mean?
On a caution sign, line thickness and any text show the character of each road (Enforcement Rule, Appendix 6). Think about which road the thick line and the thin line each stand for, and remember that even on a road with priority you must watch for vehicles coming out of side roads at the intersection.
Answer: ③
Explanation
This caution sign, with the word 'priority' on the thick vertical road, warns that a priority road crosses a non-priority road (Enforcement Rule, Appendix 6, No. 106). It is placed on the right side of the priority road 50-200 meters before the intersection. Even on a priority road, vehicles may come out of the side road, so take care at the intersection. Roundabout, traffic-light, and median-ends signs have different pictures.
Legal basis: 도로교통법 시행규칙 별표6 106 우선도로표지