Apron Markings Signs Handbook [best] Now

Specifically colored circles (often red or yellow) indicating the location of underground fuel pits.

Signs complement surface markings by providing directional information and mandatory instructions in low-visibility conditions. Apron Markings Signs Handbook

Daily checks are required to ensure paint hasn't faded and signs are not obscured by dirt or snow. Global Standards: ICAO and FAA Apron Markings Signs Handbook

Dashed or solid lines indicating the path an aircraft should follow when departing a stand. Apron Markings Signs Handbook