What does the following safety sign mean?
A caution sign picture shows the cause of the danger with symbols (Enforcement Rule, Appendix 6). You can separate similar signs by checking whether there is one vehicle or several in a line, whether arrows point in opposite directions, and whether lines narrow or a side road joins.
Answer: ②
Explanation
A picture of several motor vehicles lined up overlapping one another is a caution sign warning of a frequently congested section (Enforcement Rule, Appendix 6, No. 141). It is placed on the right side of the road 50-200 meters before sections where frequent congestion creates a risk of accidents. There may be stopped vehicles ahead, so slow down in advance and keep a sufficient safe distance from the vehicle ahead. Two-way-traffic, road-narrows, and merging-road signs have different pictures.
Legal basis: 도로교통법 시행규칙 별표6 141 상습정체구간표지