There are NO road signs. There have never been road signs.

A UN report, classified "Tippy-Tippy-Top Secret", which I have read and the gist of which I now share, reports that what we think are road signs are actually invaders from the Horse's Other End Nebula (NGC 56.2951413). When they hide in bushes they are, like the leopards that also inhabit the US, the UK, Canada and other places, simply hungry and ready to pounce upon their unsuspecting prey. (On other occassions they are answering the urgent "call of nature.") A good defense (or "defence" in those countries which are less spelling-enlightened than the US) against these creature is to bring a dog along -- the breed doesn't matter -- and let the dog sniff around the "sign." These creatures are very shy as well as very vicious and if the dog "marks" the "sign post" the critter will die of shame.

The report was classified so that the population would not panic, which populations are, according to several Government Studies, prone to do.