advice alert appropriate-behavior appropriate-behaviour avoid be-careful below-ground black cable care careful caution communicating communication concern digging digging-dangers optical-fibre-cable potential risk risks risky safety sign signs stay-clear warned warning warning-sign yellow above aerial aeroplane airplane arial below cars colors colours conditions construction development factory flight freeway ground hazy height high highways industrial looking down motor cars overpass panoramic properties rails railway lines roads roadways roofs rooves shapes streets suburbs traffic travel trees up above vehicles views homes houses blue blue-haze buildings Haze landscape looking-down outer-suburban outer-suburbs perspectives up-above vegetation wing trucks air air-industry air-travel airline airlines angles aviation beneath curved curves daylight daytime flap flying gray grey light lines metallic plane shadow shape sight silvery sky space speed sunlight transport transportation traveling travelling wings wingspan wingtips danger dangerous flammable gas gaseous natural-gas no-ignition pipeline pipes red vapour vapours white Australia green greenery ovals parks playing fields suburban