Editing Semi-trailer truck (section)

===Oceania===
====Australia====
{{Main|Road transport in Australia}}

[[Australia]]n road transport has a reputation for using very large trucks and [[road train]]s. This is reflected in the most popular configurations of trucks generally having dual drive axles and three axles on the trailers, with four tyres on each axle. This means that Australian single semi-trailer trucks will usually have 22 tyres, which is generally more than their counterparts in other countries. Super single tyres are sometimes used on tri-axle trailers. The suspension is designed with travel limiting, which will hold the rim off the road for one blown or deflated tyre for each side of the trailer, so a trailer can be driven at reduced speed to a safe place for repair. Super singles are also often used on the steer axle in Australia to allow greater loading over the steer axle. The increase in loading of steer tyres requires a permit.{{CN|date=October 2024}}

Long haul transport usually operates as B-doubles with two trailers (each with three axles), for a total of nine axles (including steering). In some lighter duty applications, only one of the rear axles of the truck is driven, and the trailer may have only two axles. From July 2007, the Australian Federal and State Governments allowed the introduction of B-triple trucks on a specified network of roads.<ref>{{cite press release |url=http://www.minister.infrastructure.gov.au/mv/releases/2007/July/114MV_2007.htm |title=Vaile Announces the B-Triple Road Network |publisher=Ministry for the Department of Infrastructure |date=9 July 2007 |archive-url=https://web.archive.org/web/20080602215035/http://www.minister.infrastructure.gov.au/mv/releases/2007/July/114MV_2007.htm |archive-date=2 June 2008}}</ref> B-Triples are set up differently from conventional road trains. The front of their first trailer is supported by the [[Fifth wheel coupling|turntable]] on the prime mover. The second and third trailers are supported by turntables on the trailers in front of them. As a result, B-Triples are much more stable than road trains and handle exceptionally well. True road trains only operate in remote areas, regulated by each state or territory government.{{CN|date=October 2024}}

In total, the maximum length that any articulated vehicle may be (without a special permit and escort) is {{convert|53.5|m|ft|abbr=on}}, its maximum load may be up to 164&nbsp;tonnes gross, and may have up to four trailers. However, heavy restrictions apply to the areas where such a vehicle may travel in most states. In remote areas such as the [[Northern Territory]] great care must be taken when sharing the road with longer articulated vehicles that often travel during the daytime, especially four-trailer road trains.{{CN|date=October 2024}}

Articulated trucks towing a single trailer or two trailers (commonly known as "short doubles") with a maximum overall length of {{convert|19|m|ft|abbr=on}} are referred to as "General access heavy vehicles" and are permitted in all areas, including metropolitan. B-doubles are limited to a maximum total weight of 62.5&nbsp;tonnes and overall length of {{convert|25|m|ft|abbr=on}}, or {{convert|26|m|ft|abbr=on}} if they are fitted with approved FUPS (Front Underrun Protection System) devices. B-doubles may only operate on designated roads, which includes most highways and some major metropolitan roads. B-doubles are very common in all parts of Australia including state capitals and on major routes they outnumber single trailer configurations.{{CN|date=October 2024}}

Maximum width of any vehicle is {{convert|2.5|m|ft|abbr=on}} and a height of {{convert|4.3|m|ft|abbr=on}}. In the past few years, allowance has been made by several states to allow certain designs of heavy vehicles up to {{convert|4.6|m|ft|abbr=on}} high but they are also restricted to designated routes. In effect, a 4.6&nbsp;meter high B-double will have to follow two sets of rules: they may access only those roads that are permitted for B-doubles ''and'' for 4.6&nbsp;meter high vehicles.{{CN|date=October 2024}}

In Australia, both conventional prime movers and [[cabover]]s are common, however, cabovers are most often seen on B-doubles on the eastern seaboard where the reduction in total length allows the vehicle to pull longer trailers and thus more cargo than it would otherwise.{{CN|date=October 2024}}

<gallery align="center" mode="packed">
File:B double logging truck in Australia.jpg|An Australian [[Tractor unit|prime mover]] [[Kenworth]] and B double trailer combination
File:Road Train2.jpg|[[Volvo]] [[road train]] in Australia
File:Red B-double truck.jpg|B-double truck on the [[Sturt Highway]]
</gallery>

====New Zealand====
New Zealand legislation governing truck dimensions falls under the Vehicle Dimensions and Mass Rules, published by [[NZ Transport Agency]].<ref>{{cite web |url=https://www.nzta.govt.nz/assets/resources/factsheets/13/docs/13-vehicle-dimensions-and-mass.pdf |title=Vehicle Dimensions and Mass Guide |publisher=[[NZ Transport Agency]]}}</ref> New rules were introduced effective 1 February 2017,<ref>{{cite web |url=https://www.drivingtests.co.nz/resources/vehicle-dimensions-and-mass-vdam-changes/ |title=Vehicle dimensions and mass (VDAM) changes|date=13 February 2017}}</ref> which increased the maximum height, width and weight of loads and vehicles, to simplify regulations, increase the amount of freight carried by road, and to improve the range of vehicles and trailers available to transport operators.{{CN|date=October 2024}}

Common combinations in New Zealand are a standard semi-trailer, a [[Road train#B-double|B-double]], or a rigid towing vehicle pulling a trailer with a drawbar, with a maximum of nine axles. Standard maximum vehicle lengths for trailers with one axle set are:
* Semi-trailer: {{convert|19|m|ft|abbr=on}}
* Simple: {{convert|22|m|ft|abbr=on}}
* Pole: {{convert|20|m|ft|abbr=on}}
Trailers with two axle sets can be {{convert|20|m|ft|abbr=on}} long, including heavy rigid vehicles towing two trailers.
Oversized loads require, at minimum, a permit, and may require one or more pilot vehicles.<ref>{{cite web |url=https://www.nzta.govt.nz/assets/resources/factsheets/53/docs/53-overdimension.pdf |title=Overdimension vehicles and loads |publisher=[[NZ Transport Agency]]}}</ref>

'''High-productivity motor vehicle''' (HPMV) permits are issued for vehicles exceeding 44 tonnes, or the above dimensions.<ref>{{Cite web|date=1 May 2021|title=Land Transport Rule – Vehicle Dimensions and Mass 2016 – Rule 41001/2016|url=https://www.nzta.govt.nz/assets/resources/rules/docs/vehicle-dimensions-and-mass-2016-as-at-1-may-2021.pdf|website=NZTA}}</ref> Trucks up to 62 tonnes were allowed, with an initial bridge strengthening program costing $12.5m.<ref>{{Cite web|date=2013-07-27|title=More monster trucks to thunder along our roads|url=https://www.stuff.co.nz/waikato-times/news/8972026/More-monster-trucks-to-thunder-along-our-roads|access-date=2021-05-04|website=Stuff|language=en}}</ref>