Seoul has hundreds of elementary schools in the city and every time you go near one, you'll see one of these signs. 어린이 보호 구역(eorini boho guyeok) means 'school zone', with 어린이 meaning children, 보호 meaning protection and 구역 meaning zone or area.
The '천천히'(cheon cheon hi = slow down) rule isn't really strictly abided by, but these days you see more and more volunteer moms who stand at major crosswalks around the hours when the school starts and ends, sort of controling the traffic in the narrow streets around the schools.
