's earliest needs for trade and travel were met by narrow bush tracks, used by tribes of Indigenous Australians
prior to European settlement. The formal construction of roads began in 1788 in the newly formed colony of New South Wales
. Road construction programs in the early 19th century were generally underfunded, as they were dependent on government budgets, loans, and tolls, while there was a huge increase in road usage, due to the Australian gold rushes
. Local government authorities
, often known as Road Boards, were therefore established to be primarily responsible for funding and undertaking road construction and maintenance. The early 1900s saw both the increasingly widespread use of motorised transportation, and the creation of state road authorities in each state
, between 1913 and 1926, to manage each state's arterial road network. The federal government became involved in road funding in the 1920s, distributing funding to the states. The depression of the 1930s slowed the funding and development of the major road network until the onset of World War II. Supply roads leading to the north of the country were considered vital, resulting in the construction of Barkly, Stuart, and Eyre highways.
The decades following the war saw substantial improvements to the network, with freeways established in cities, many major highways sealed, development of rural roads in northern Queensland and Western Australia, and interstate routes upgraded. In 1974, the federal government assumed responsibility for funding the nation's most important road links, between state and territory capital cities, which were declared National Highways. Those roads were gradually improved, and by 1989, all gravel road sections had been sealed. In the following decades, the National Highway system was amended through legislation, and was eventually superseded in 2005 by the broader National Land Transport Network, which includes connections to major commercial centres, and intermodal freight transport facilities.
The first route marking system was introduced to Australia in the 1950s. National Routes were assigned to significant interstate routes – the most important road links in the country. National Route 1 was designated to a circular route around the Australian coastline. A state route marking system was designed to supplement the national system, for inter-regional and urban routes within states. When the National Highway system was introduced, National Routes along it became National Highway routes with the same numbers, but with distinctive green and gold route markers. During the late 1970s, planning began for a new alphanumeric route system in the state of Tasmania. Alphanumeric routes have since been introduced in most states and territories in Australia, partially or completely replacing the previous systems.