(A) Every operator of a vehicle or other conveyance traveling upon any street intersecting any through street herein designated shall bring such vehicle or conveyance to a full stop at the stop sign posted at such intersection or at a clearly marked stop line before entering the intersection; subject, however, to the direction of any police officer or traffic control signal at such intersection.
(B) The operation of any vehicle or conveyance which has come to a full stop as required above, upon entering the through street, as well as operators of vehicles on such through streets, shall be subject to the usual right-of-way rule prescribed by law and applicable to vehicles at intersections.