(A) Those streets and parts of streets described in Chapter 75 Schedule II, attached hereto and made a part hereof, are hereby declared to be through streets for the purpose of this section.
(B) When stop signs are placed upon highways which intersect a through street, the driver shall bring his vehicle to a stop before entering the intersection, and he shall not proceed into or across the through street until he has first determined that no conflict with traffic will ensue.
('70 Code, Ch. E, Art. VI § l) Penalty, see § 70.99