access airport airport-terminal blue communicating communication directional-signs doors exit informative informing inside interior open open-doors passengers pedestrians signs travel travellers travelling way-out conveniences glass lift over-pass windows arrow black black-on-white direction directional gray grey indication law no-alternative one-way one-way-signs only pointer pointing reflective sign specific street-sign traffic traffic-flow traffic-sign white advice advising communications directing indicator satellite-station space space-technology technology tracking weathered wording words acceptable allocated allocation appropriate-behavior appropriate-behaviour approved carpark parking public red word humor humorous humour lane laneway name nomenclature street-name unusual symbol symbols additional extra green announcement appearance bilingual cambodian declaration detail english khmer lettering message notice notification observant observe surface surfaces letter off-road parking-bay pullover roadside