blue lorry no not pole post posts prohibition red road sign signpost signs sky steel stop traffic truck vehicle yellow cannon circle conflict enemy mandatory peace politics prohibitory roadsign roadsigns tank war warning wars auto bus buses busses car minibus pylon transport transportation travel alert back ban banned caution entry exit go plate prohibited street way chinese clever knowledge letter nonsence rule rules stopped strange ting understand understandable advice authority availability available checkered checks communicating communication law mobile mobility motor-bike motor-cycle on-duty order police police-only power regulations responsibility responsible restricted restrictions road-work security symbols lamp sad city right signalling square ahead around the bend Australia bend building buildings cars CBD commute commuting complex curve direction freeway height high highrise highway lamp-posts left-hand driving main road merging merging traffic motor cars motor vehicles office office complex office highrise perspectives road rules road signs skirting the city centre speed traffic flow traffic lanes vehicles care ducks stone writing bridge tunnel