Editing Route number (section)

====Alphanumeric routes====
Tasmania introduced an alphanumeric route numbering system in 1979, based on the British system from 1963. The new system aimed to upgrade the signing of destinations, including previously unmarked roads, and to simplify navigation by allowing visitors to follow numbered routes. [[Highway 1 (Tasmania)|National Highway&nbsp;1]] was retained as the only route without an alphanumeric designation.<ref name=TRRC>{{cite web |title=Tasmanian Road Route Codes: Route descriptions and focal points |url=http://dpipwe.tas.gov.au/Documents/Route%20Descriptions.pdf |publisher=Government of Tasmania |author=Department of Primary Industries, Parks, Water & Environment |archive-url=https://web.archive.org/web/20140714161713/http://dpipwe.tas.gov.au/Documents/Route%20Descriptions.pdf |archive-date=14 July 2014 |url-status=live |pages=6, 60–64 |date=January 2014 |version=Version 2.7 |access-date=10 April 2014}}</ref>
In the 1990s [[Victoria (Australia)|Victoria]] and [[South Australia]] also overhauled their systems.{{citation needed|date=January 2014}} While South Australia discarded the National and State Route Numbering Systems, those shield-based schemes were retained in the Melbourne metropolitan area as the [[List of old road routes in Victoria|Metropolitan Route Numbering Scheme]].<ref name="VicRoads signs">{{cite web |title=Direction Signs and Route Numbering (non-Freeway) |url=http://www.vicroads.vic.gov.au/NR/rdonlyres/62F8B797-D2D1-49C9-8B8D-E40DAD6105D6/0/TEM2Ch10.pdf |work=Traffic Engineering Manual, Chapter 2 - Edition 1 |publisher=[[VicRoads]]|access-date=10 May 2014|archive-url=https://web.archive.org/web/20160406005845/https://www.vicroads.vic.gov.au/NR/rdonlyres/62F8B797-D2D1-49C9-8B8D-E40DAD6105D6/0/TEM2Ch10.pdf |archive-date=6 April 2016 |url-status=live |pages=21–35 |date=2001}}</ref> The route numbers used in the alphanumeric schemes were generally inherited from the original National Route Numbering System, with only a few exceptions, and 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 extensively in the Melbourne metropolitan area where the blue-shield metropolitan route system is retained for most routes. (They were phased out for motorways in the early 2010s. New alphanumeric numbers are appearing for other new roads, and cover plates for signs, possibly pointing to a future phase-out of the metropolitan route system altogether.) The National Highways were retained, but with the route numbers changed to alphanumeric designations (later to be passively phased out since 2014).

New South Wales and the [[Australian Capital Territory]]{{efn|The only numbered roads in the Australian Capital Territory are interstate highways from NSW and their interconnecting thoroughfares, as the Australian Capital Territory does not number its other highway or freeway grade roads.}} introduced the alphanumeric system from early 2013.<ref name=RMS/> Before being officially announced, new road signs were fitted with such numbers and then being "coverplated" with the existing route number. However, the new system does not distinguish between the former National Highways and other routes.

Alphanumeric routes have also been introduced for many major highways and urban routes in [[Queensland]], although many other roads retain markers from the National Route, National Highway, State and Metroad numbering systems. According to the New South Wales [[Roads & Maritime Services]], the Northern Territory has similarly begun converting their numbered routes to alphanumeric routes, with a "progressive replacement" scheme that sees alphanumeric route markers introduced only when signs are replaced.<ref name="RMS alpha QandA">{{cite web|title=Questions and answers: A better way to navigate NSW roads|url=http://www.rms.nsw.gov.au/roadprojects/projects/alpha_numeric/documents/factsheets/qanda.pdf|publisher=New South Wales Government|access-date=16 May 2014|department=Roads & Maritime Services|archive-url=https://web.archive.org/web/20140516123848/http://www.rms.nsw.gov.au/roadprojects/projects/alpha_numeric/documents/factsheets/qanda.pdf|archive-date=16 May 2014|url-status=live}}</ref> There are no plans to introduce an alphanumeric route numbering system in [[Western Australia]].<ref name="MRWA signs">{{cite web|title=Route Numbering|url=https://www.mainroads.wa.gov.au/BuildingRoads/StandardsTechnical/RoadandTrafficEngineering/TrafficManagement/DirectionalSignsGuidelines/Pages/Guidelines_for_Direction_Signs_in_the_Perth_Metropolitan_Area.aspx|work=Guidelines for Direction Signs in the Perth Metropolitan Area|publisher=[[Main Roads Western Australia]]|access-date=17 November 2013|archive-url=https://web.archive.org/web/20131021152024/https://www.mainroads.wa.gov.au/BuildingRoads/StandardsTechnical/RoadandTrafficEngineering/TrafficManagement/DirectionalSignsGuidelines/Pages/Guidelines_for_Direction_Signs_in_the_Perth_Metropolitan_Area.aspx|archive-date=21 October 2013|url-status=live|date=21 September 2011|quote=Main Roads has chosen to retain the shield numbering system}}</ref>

=====Prefix letters=====
In the alphanumeric systems, a letter denoting the route's construction standard and function is prefixed to the route number, creating an alphanumeric route designation. One of six letters may be used:
* "M" routes are primary traffic routes, called motorways in some states. These are typically [[dual carriageway]], [[freeway]]-standard highways, but may also be used for rural roads that are nearly at freeway-standard,<ref name="QLD signs">{{cite web|title=Part 15: Direction signs, information signs and route numbering|url=http://www.tmr.qld.gov.au/~/media/busind/techstdpubs/Manual%20of%20Uniform%20Traffic%20Control%20Devices/MutcdPart15Directioninfoandroute.pdf|work=Manual of Uniform Traffic Control Devices|access-date=18 April 2014|publisher=Department of Transport & Main Roads|archive-url=https://web.archive.org/web/20140418113035/http://www.tmr.qld.gov.au/~/media/busind/techstdpubs/Manual%20of%20Uniform%20Traffic%20Control%20Devices/MutcdPart15Directioninfoandroute.pdf|archive-date=18 April 2014|url-status=live|pages=55–56|date=14 March 2014}}</ref> or at least are dual carriageways.<ref name="VicRoads signs" />
* "A" routes are other primary highways, including urban arterials<ref name="QLD signs" /> and interstate or interregional single carriageways.<ref name="VicRoads signs" /><ref name="QLD signs" />
* "B" routes are less significant routes, either as an alternative to an "A" or "M" route, or linking smaller population centres to larger regional centres, but without being a major through-route in the region.<ref name="QLD signs" /> These are the major road links in areas without "A" routes.<ref name="VicRoads signs" />
* "C" routes link smaller settlements and towns to the rest of the major road network.<ref name="VicRoads signs" /> They are used for roads without the significance of an "M", "A", or "B" route, but where numbering would assist navigation.<ref name="QLD signs" />
* "D<nowiki>''</nowiki> routes are detour routes for motorways. There are only two of them, D1 and D5
* "R" routes are ring routes in South Australia. There is only one route, R1