(a) Except when directed to proceed by a police officer or traffic control signal, every driver of a vehicle approaching a stop intersection described in appendix I, section 124 of this code and indicated by a stop sign shall stop before entering the crosswalk on the near side of the intersection, or, in the event there is no crosswalk, shall stop at a clearly marked stop line, or, if known then, at the point nearest the intersecting roadway where the driver has a view of approachingtraffic on the intersecting roadway before entering the intersection.
(b) The driver having stopped in obedience to a stop sign at an intersection shall proceed cautiously yielding the right-of-way to all vehicles not so obliged to stop which are approaching the intersection.