crossing guard

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A person who directs vehicular traffic so that pedestrians may cross the right of way.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who helps people (especially children) at a traffic crossing