air-traffic-control aircraft airport architectural architecture aviation command communications control control-tower directions directives flight fly flying height high safety tower tower-signals tower-views tracking traffic visibilty appropriate-behavior appropriate-behaviour asphalt black blue bollards care careful caution changes changing communicating communication cones delineators directive footpath information informing message red road-junction road-sign road-surface roads roadside sign signage signs slow-down slower speed-reduction street street-sign T-junction temporary thoroughfare traffic-cones traffic-flow uneven-surfaces warning white witches-hats wording words advice danger directing direction directional Dirt dirty old railway-sign risks stop warning-lights weathered denied not allowed not-permitted parking permission denied prohibited prohibition purple verge 2014 accident dangerous flipped insurance unsafe van board curve road yellow boat harbour pilot boat sea ship sunset water 80 cars speed cone hazard orange light lights sky transport transportation