The traffic engineer may make regulations designating and describing arterial highways
and through streets, and he shall 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 or arterial highway unless traffic
at any such intersection is controlled at all times by traffic-control signals; provided,
however, that the intersection of two such through streets or arterial highways or
a through street and arterial highway or at the intersection of a through street or
arterial highway and a heavy traffic street not so designated, stop signs shall be
erected at the approaches of either of the streets as may be determined by the traffic
engineer upon the basis of an engineering and traffic study.
