75 Pa. C. S. § 3323. Stop signs and yield signs

    (a) INTERSECTIONS CONTROLLED BY SIGNS.-- Preferential right-of-way at an intersection may be indicated by stop signs or yield signs as authorized in section 6124 (relating to erection of traffic-control devices at intersections).
 
   (b) DUTIES AT STOP SIGNS.-- Except when directed to proceed by a police officer or appropriately attired persons authorized to direct, control or regulate traffic, every driver of a vehicle approaching a stop sign shall stop at a clearly marked stop line or, if no stop line is present, before entering a crosswalk on the near side of the intersection or, if no crosswalk is present, then at the point nearest the intersecting roadway where the driver has a clear view of approaching traffic on the intersecting roadway before entering If, after stopping at a crosswalk or clearly marked stop line, a driver does not have a clear view of approaching traffic, the driver shall, after yielding the right-of-way to any pedestrian in the crosswalk, slowly pull forward from the stopped position to a point where the driver has a clear view of approaching traffic The driver shall yield the right-of-way to any vehicle in the intersection or approaching on another roadway so closely as to constitute a hazard during the time when the driver is moving across or within the intersection or junction of roadways and enter the intersection when it is safe to do so.
 
   (c) DUTIES AT YIELD SIGNS.-- The driver of a vehicle approaching a yield sign shall in obedience to the sign slow down to a speed reasonable for the existing conditions and, if required for safety to stop, shall stop before entering a crosswalk on the near side of the intersection or, if none, then at the point nearest the intersecting roadway where the driver has a view of approaching traffic on the intersecting roadway before entering After slowing down or stopping, the driver shall yield the right-of-way to any vehicle in the intersection or approaching on another roadway so closely as to constitute a hazard during the time the driver is moving across or within the intersection of roadways If a driver is involved in a collision with a vehicle in the intersection or junction of roadways after driving past a yield sign, the collision shall be deemed prima facie evidence of failure of the driver to yield the right-of-way.