crossing guard

CIDE DICTIONARY

crossing guard, n. 

 a person who stands at a street crossing to assist children to cross the street safely; -- usually used near schools during the times that children are entering or leaving the school.
"Crossing guards may be employed by a municipality as auxiliary police officers, or may be unpaid volunteers. Some wear uniforms, others do not. They are commonly older citizens who are retired or not employed full-time at other tasks. At some schools, older students from the school are trained to perform the function of crossing guards."  [PJC]