22352(b)(2) When approaching or passing a school building or the grounds
thereof, contiguous to a highway and posted with a standard "SCHOOL"
warning sign, while children are going to or leaving the school
either during school hours or during the noon recess period. The
prima facie limit shall also apply when approaching or passing any
school grounds which are not separated from the highway by a fence,
gate, or other physical barrier while the grounds are in use by
children and the highway is posted with a standard "SCHOOL" warning
sign. For purposes of this subparagraph, standard "SCHOOL" warning
signs may be placed at any distance up to 500 feet away from school
grounds.