Circular highway shield

A highway shield or route marker is a sign denoting the route number of a highway, usually in the form of a symbolic shape with the route number enclosed. As the focus of the sign, the route number is usually the sign's largest element, with other items on the sign rendered in smaller sizes or contrasting colors. Highway shields are used by travellers, commuters, and all levels of government for identifying, navigating, and organising routes within a county, state, province, or country. Simplified highway shields often appear on maps.

There are several distinct uses for the highway shield:

Australia has maintained distinctly different trends pertaining to Highway shields in the past and will continue in this vein somewhat, despite the conversion to alpha-numeric routes and shields. Alpha-numeric route numbering has been in use in Tasmania since the 1970s. However, from 1996 states on the mainland began conversion to the alpha-numeric system. The state of Victoria was the first to implement the policy. Prior to this conversion and concurrently, Federal Highway (gold-on-green squared-off bullet), National Highway (black-on-white squared-off bullet), State Highway (blue bullet) and Tourist Route (white-on-brown rounded pentagon) shields existed. In Victoria Freeway shields were used (white-on-green with 'F' prefix) until the late 1980s, while during the 1990s Queensland and New South Wales implemented a hexagonal blue-on-white Metroad system of urban arterial routes. With the opening of the Western Ring Road (now M80); that road used a shield quite similar to the U.S. Interstate shield, albeit with 'Ring Road' written instead of 'Interstate' and with 2 peaks, rather than 3. To further complicate matters, with the introduction of the alpha-numeric system, roads that are federally funded (or Federal Highways) have a squared-off bullet encompassing the alpha-numeric designation. Freeways and dual-carriageway roads often use an 'M' prefix, particularly in Victoria. In addition, trapezoidal signs are placed every 5 km on major regional highways and freeways indicating the distance to the post office of the next city or major town on the route. These signs usually only have the first letter of the destination; two or three letters are used if there is ambiguity between nearby towns or when the place name consists of two words.

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