Certain intersections described in Chapter 75 Schedule III, attached hereto and made a part hereof, are hereby declared to be stop intersections when entered from the streets last named. When stop signs are placed at such intersections, every driver of a vehicle shall 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 § 2) Penalty, see § 70.99