This is a list of highways in Australia, listed alphabetically along with its route number and location. Note that some highways service more than one state or territory.
Australia is a vast and sparsely populated country. Its earliest highways radiate in a spoke-like pattern from capital cities in each State. These highways link major country towns to the capital cities. Intercapital transport was initially mainly by sea and rail.
As the population increased, roads connecting the towns located on different highways were constructed. Victoria, for example, has the largest highway network, with every major town linked directly to every other major town in the state. Increased demand for freight and passenger transport led to construction of intercity highways, altough much freight still goes by rail.
National Route Numbering System
In 1955, the Australian National Route Numbering System was introduced to simplify navigation across Australia. The National Route Numbers are marked by white shields which are present in directional signs, distance signs or trailblazers. The general rule is that odd-numbered highways travel in north-south directions and even-numbered highways in east-west directions, with only a few exceptions. National Route 1 was assigned to a network of highways and roads which together linked all capital cities and coastal towns circumnavigating the mainland.
In the 1970s the National Highway scheme was introduced. It is made up of highways that give the most direct point-to-point route between capitals. These highways are federally funded. They are recognised by their distict green and gold shields.
The National Route system initially linked the centres of towns and cities and terminated at the junction of other national routes. The growth of bypasses around towns and cities changes the situation somewhat. In the 1990s, with the introduction of internal metropolitan route system (or Metroads), National Routes terminate at the metropolitan city limits rather than the individual city centres.
State Route Numbering System
Important urban and inter-regional routes not covered by the National Highway or National Route systems were marked under the State Route system. They are recognised by blue shield markers. They were practically adopted in all states by the end of the 1980s. In some states, some lesser important National Routes had their status downgraded to State Routes.
In the NSW, they are also adopted in metropolitan areas of Wollongong and Newcastle using three-digit numbers instead of two-digit found elsewhere. This was also the case in rural Victoria, until they were eventually superceded with the alphanumeric system.
Alphanumeric Route Numbering System
In the 1990s there was a major change to the route marking systems. Victoria and South Australia had completely overhauled their systems. They discarded the National Route Numbering System and introduced the alphanumeric marking scheme following the example set by Tasmania in the late 1970s.
The route numbers inherited from the original National Route Numbering System remains with a few exceptions, however they are now prefixed with letters denoting their grade. For example, Western Freeway is M8 until Ballarat and continues beyond as A8 Western Highway.
They are not used in metropolitan areas and instead the blue-shield state route system is retained.
"M" Routes
Primary highways. These are typically dual carriageway freeway standard highways. They connect capital cities to each other or to bigger rural cities and also applicable to major city freeways. Interchanges may either be graded or level. They carry high volume of traffic and bypass settlements, towns and sometimes cities.
"A" Routes
Single carriageway interstate or interregional primary highways. Traffic volume less than "M" routes but with ample overtaking lanes, sealed shoulders and markings. Constructed and built to excellent quality. They may pass through or bypass town centres.
"B" Routes
Secondary highways linking together major towns on different "A" routes including certain lesser important former national routes. In addition, they may include be major bypassed sections of former "A" or "M" routes and significant tourist routes. They are reasonably good quality sealed roads with shoulders either sealed or not.
"C" Routes
Roads linking smaller settlements and towns to "A", "B" or "M" routes. May also be applied to short bypassed sections of former "A" routes. Fully sealed surface but of moderate to poor quality and may or may not have shoulders.
Metropolitan Route Numbering System
In the 1990s, urban route numbering system were streamlined in the new Metroad scheme. They are recognised by distinctive hexagon shields and superseded the state route, freeway and National Route schemes along their path. Metroads radiate in a spoke pattern from city centres to highways outside metropolitan limits. In addition, Metroads also cover major city ring roads. Metroads are made of urban highways, main roads and urban freeways. Currently Metroads are found in Sydney and Brisbane.
Non-Metroads retain the earlier state route system.
