(1) After the operator has stopped at the entrance to a through-street, such operator shall yield the right-of-way to all vehicles and street cars approaching in either direction on such through-streets, as required by The Vehicle Code.
(2) After the operator has stopped in obedience to a stop sign at an intersection where a stop sign is erected at one or more entrances thereto such operator shall yield the right-of-way to all vehicles and street cars which are not so obliged to stop and which are within or about to enter the intersection, as required by The Vehicle Code.
(3) This Section shall not operate to relieve any operator having the right-of-way from the duty to operate his vehicle or street car with due regard for the safety of vehicles or street cars entering such through-street or stop intersection, nor shall it protect any operator having the right-of-way, as required by The Vehicle Code.