Every state and province has different markers for its own highways, but use standard ones for all federal highways. Many special highways – such as the Queen Elizabeth Way, Trans-Canada Highway, and various auto trails in the U.S. – have used unique signs. Counties in the US sometimes use a pentagonal blue sign with yellow letters for numbered county roads, though the use is inconsistent even within states.
Units[edit]
Distances on traffic signs generally follow the measurement system in use locally: that is to say, the metric system in all countries of the world except Burma, Liberia, the United Kingdom, and the United States – although the metric system is used in the UK for all purposes other than the display of road distances and the defining of speed limits, and in the US the Federal Department of Transportation has developed (very rarely used) metric standards for all signs.