When stop signs or signals are erected pursuant to the Plans at or near the entrance to any intersection in the parking area, every operator of a vehicle shall stop such vehicle at such sign or signal or at a clearly marked stop line before entering the intersection except when directed to proceed by a police officer.
After the operator of a vehicle has stopped in obedience to a stop sign or signal at an intersection in the parking area where a stop sign Is erected at one or more entrances thereto, such operator shall proceed cautiously, yielding to vehicles not so obliged to stop which are within the Intersection or approaching so closely as to constitute an immediate hazard, but may then proceed.
Appropriate stop signs or signals shall be erected in conformity with the Plans.