Yellow Road Marker. - Yellow Cat's Eyes, Road Studs Or Retroreflective Raised Pavement Markers (RRPMs) Are Used To Visually Reinforce A Yellow No-passing Line. The Painted Passing Line Can Be Less Visible When The Road Is Wet. Usually A White Cat's Eye Is Used In The Centre Of The Road If Overtaking Is Permitted. If Yellow Cat's Eyes Are Present They Are Bi-directional If The Line Is Applicable In Both Directions, Or Mono-directional If It's Only Applicable In One Direction And Spaced Every 10m. On Unlit Rural Roads The Markers Are In Groups Of Four, One Metre Apart, With 10m Between Each Group. Only One Of The Group Of Four Road Studs Is Required To Be Reflective. On No Overtaking Advance Warning Lines They Are Spaced 20m Apart. The Yellow Cats Eyes Are The Same Kind As Used In The UK Or Australia And They Are Used In The Same Manner. Photo