Those streets and parts of streets described
in Schedule I on file in the office of the City Clerk are hereby declared
to be through streets for the purpose of this section.
Whenever any ordinance of this City designates
and describes a through street, it shall be the duty of the Director
of Public Works or his/her designee to place and maintain a stop sign
or, on the basis of an engineering and traffic investigation at any
intersection, a yield sign on each and every street intersecting such
through street unless traffic at any such intersection is controlled
at all times by traffic-control signals; provided, however, that at
the intersection of two such through streets or at the intersection
of a through street and a heavy traffic street not so designated,
stop signs shall be erected at the approaches of either of said streets
as may be determined by the Director of Public Works or his/her designee
upon the basis of an engineering and traffic study.