National Class 3 4.6m High Semitrailer Dimension Exemption Notices Operator's Guide

The National Class 3 Heavy Vehicle 4.6m High by Construction Semitrailer Dimension Exemption Notice 2024 (No.1) and the New South Wales and Queensland Class 3 4.6m High Loaded Semi-Trailer Dimension Exemption Notice 2024 (No.1) provide dimension exemptions when operating within eligible combinations under these Notices.

These Notices provide operators of semitrailers (used in a combination) to operate higher than 4.3m but no higher than 4.6m with greater flexibility.

The purpose of these Notices is to exempt a stated category of Class 3 heavy vehicles from the height limit stated in section 8 of Schedule 6 of the Heavy Vehicle (Mass, Dimension and Loading) National Regulation (MDL).

This instrument does NOT exempt these vehicles from other requirements of the Heavy Vehicle National Law (HVNL),including, but not limited to, mass and other dimension requirements.

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Specifications
Gazette Notices:	C2024G00105 C2024G00116
Starts:	10 February 2024
Expires:	9 February 2029
Vehicle types:	Class 3, 4.6m high semitrailer in a combination
Exemptions:	Dimension requirements (height by load, height by construction)
Law:	MDL
*Coverage:	NSW, QLD, SA, VIC
To be carried:	No

*Specific state conditions are explained below.

Overview

The information in this Operator’s Guide is intended to do two things:

Explain how the National Class 3 Heavy Vehicle 4.6m High by Construction Semitrailer Dimension Exemption Notice 2024 (No.1) and the New South Wales and Queensland Class 3 4.6m High Loaded Semi-Trailer Dimension Exemption Notice 2024 (No.1) (the Notice/s), to assist in complying with them. It is important to remember this Operator’s Guide is instructional only and it is the Notice that provides the exemption or authorisation. If there is a difference or misunderstanding between the Operator’s Guide and the Notice, the Notice has priority and must be followed. The only exceptions are the requirements or conditions set out in the ‘Network and Mapping’ section explained below.
Provide additional information referred to in the network requirements of the Notice. This includes links to network maps and other information such as vehicle, travel and road conditions. Networks and their conditions published in the ‘Network and Mapping’ section of this Operator’s Guide are not general advice and must be treated as conditions of the Notice.

Please read the Notice and this Operator’s Guide together. To download or print this guide, use the print or PDF buttons on the top right of this page.

About these Notices

These Notices will provide operators of semitrailers (used in a combination) to operate higher than 4.3m but no higher than 4.6m with greater flexibility.

It will also reduce the number of permits that local government road managers need to assess.

Exemptions

These exemptions only apply to the extent to which conditions are granted.

Dimension requirements

Exempts a stated category of Class 3 heavy vehicles from:

the height limit stated in section 8 of Schedule 6 of the MDL.

Note: These Notices exempt semitrailers higher than 4.3m but no higher than 4.6m from height limits in the MDL. These Notices do NOT exempt these vehicles from other requirements of the Heavy Vehicle National Law (HVNL), including mass and other dimension requirements.

Term	Definition
4.6m high loaded semitrailer	Means a semitrailer used in a combination that, together with its load, is higher than 4.3m but not higher than 4.6m; but does not include a class 1 heavy vehicle.
4.6m high semitrailer	Means a semitrailer, used in a combination, that: is constructed higher than 4.3m but not constructed higher than 4.6m; and; does not include a class 1 heavy vehicle.
Load support height	Means the perpendicular distance from the ground to the level at which a load is supported on a semitrailer. This includes: the area ordinarily considered a deck; and the floor of a bin or tank that is integral to the trailer; and any other load-bearing points such as the frame of a skeleton trailer or vehicle carrier; and any area above an axle group under a fifth wheel coupling, measured from the ground to the level at which the towed unit is supported by the coupling.
Semitrailer length	Means the distance from the front of the semitrailer to the rear of the semitrailer, not including any load.

Eligible vehicles

To be eligible to operate under these Notices, approved combinations must comply with all requirements of the MDL.

**Table 1:** Eligible vehicles
Combination	NSW	QLD	SA	VIC
A combination consisting of a prime mover and a 4.6m high semitrailer
B-double
Road train
Any heavy vehicle that is Class 1 or 3

Conditions

Notices are subject to various conditions to ensure public safety, protect assets and prevent adverse impacts on the community, such as noise, emissions and traffic congestion. See the sections below for specific conditions related to these Notices.

A B-double must comply with all conditions of the National Class 2 Heavy Vehicle B-double Authorisation Notice.

A road train must comply with all conditions of the National Class 2 Heavy Vehicle Road Train Authorisation Notice.

A semitrailer constructed to a height greater than 4.3m must have an air suspension system with effective dampers fitted to the vehicle.

Queensland special conditions - Click to expand

Any load carried under these Notices must be loaded in a way that maximises continuous contact at the lowest deck of the trailer. This includes shipping containers raised above the lower deck of a semitrailer, as shown in Figure 1.

A 4.6m high semitrailer cannot be used as a component of a road train. Under the HVNL, a road train includes a B-triple.

Figure 1: Containers chocked up on the lower deck section of a trailer are ineligible to operate under these Notices when travelling in Queensland.

picture is of a container chocked up on a lower deck section of a tri-axle trailer

New South Wales special conditions - Click to expand

Twist locks must secure freight containers transported by heavy vehicles under these Notices. This condition applies whether the container is laden or unladen and whether certified for marine use or not.

Note: Failure to secure a container is a breach of HVNL load restraint requirements.

Mass limits - Click to expand

Mass limits for combinations

**Table 2:** Mass limits for combinations
Combination	Mass limits type	NSW
A combination consisting of a prime mover and a 4.6m high semitrailer	Total combination mass limit	No greater than 90% of the prescribed mass limits in the MDL.
B-double	Total combination mass limit	No greater than 90% of the lesser of: the prescribed mass limits in the MDL; and the mass limit applying under the National Class 2 B-double Authorisation Notice.
Road train	Total combination mass limit	No greater than 90% of the lesser of: the prescribed mass limits in the MDL; and the mass limit applying under the National Class 2 Road Train Authorisation Notice.

For more information on mass and dimension limits, see General mass and dimension limits.

Note: These Notices do not apply conditions to axle group mass limits - so whichever limits would normally apply continue to apply.

Load support height conditions - Click to expand

A minimum 50% of the total of length of semitrailers must be at a height no greater than 1.2m.

This requirement applies to each semitrailer. In the diagram below of Figure 2 that shows a B-double, both semitrailers must comply with the requirement, i.e.:

Length A (at a height greater than 1.2m) must not be greater than then length B.
For the second trailer, C must not be greater than D.

Figure 2: Illustration of deck length measurements.

picture is of two tri-axle trailers with labelled deck length measurements

If a trailer in the combination has a height no greater than 4.3m – the deck height limitations described here do not apply to that trailer.

Load support height means:

the area ordinarily considered a deck;
the floor of a bin or tank that is integral to the trailer;
any other load-bearing points such as the frame of a skeleton trailer or vehicle carrier;
any area above an axle group under a fifth wheel coupling, measured from the ground to the level at which the towed unit is supported by the coupling.

Network and mapping

For the purposes of s121 of the HVNL, an area or route specified in the 'Network & Mapping' section of this Operator's Guide is a stated area or route to which this Notice applies. In addition to complying with the conditions stated in this Operator's Guide, operators must ensure compliance with the specific road manager access requirements set out below or in network maps.

In this tab, you will find the approved routes authorised under these Notices. There may also be network conditions pursuant to the stated areas and routes under these Notices. Network conditions relate to road and travel conditions that are not contained within these Notices.

4.6m semitrailer combinations may access the routes authorised under these Notices. Approved routes are a combination of areas (all roads within a defined area) and specific roads.

National Network Map

This Notice may refer to state or territory government websites for the publication of networks. From 20 December 2023, certain authorised heavy vehicle road network maps for the Australian Capital Territory, New South Wales, Queensland, South Australia, and Victoria are published by the National Heavy Vehicle Regulator, through the NHVR National Network Map. Additional information and guidance can be found on the National Network Map webpage.

Specified road manager network requirements

The following section outlines specific road manager network requirements under the Notice, including route conditions, restrictions, and non-participating road managers.

Road manager network requirements in this section may change from time to time and should be reviewed regularly to ensure compliance.

For further information on how to comply with a requirement, please contact the relevant road manager.

Road managers may publish specific route conditions and restrictions on the approved network map. These must be complied with in addition to any route requirements outlined in this Operator's Guide. If a condition listed in any section of this Operator's Guide conflicts with a route condition or restriction published on an approved network map, the more restrictive requirement applies.

Approved routes covered by the Notices

The following routes are approved for travel for vehicles eligible under these Notices.

**Table 3:** Approved routes covered by the Notices
Combination	NSW	QLD	SA
A combination consisting of a prime mover and a 4.6m high semitrailer	Click on 4.6m High Vehicles on the TfNSW Restricted Access Vehicle maps and lists page.	General Access
B-double	Select the relevant B-double type under GML and CML networks on the TfNSW Restricted Access Vehicle maps and lists page.	As per the access under the National Class 2 B-double Authorisation Notice.
Road train	Select the relevant road train type under GML and CML networks on the TfNSW Road train maps page.	No access (a 4.6m high semitrailer cannot be used as a component of a road train in Queensland).	As per the access under the National Class 2 Road Train Authorisation Notice.

South Australia conditions - Click to expand

Local conditions for heavy vehicle combinations operating under the national Notice in South Australia are available in Table 4.

**Table 4:** Local South Australian council network conditions
Council name	Restriction information
District Council of Ceduna	Restricted speed loaded or unloaded to 80km/h on sealed council-maintained roads outside town limits. Restricted speed loaded or unloaded to 70km/h on unsealed council-maintained roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. Restricted Access Vehicle (RAV) operators are required to inspect all unsealed routes which have received greater than 15mm of rain in the preceding 24 hours to ensure that the pavement will not be damaged by the RAV operation.
District Council of Cleve	All council gazetted roads have a 70km/h speed restriction.
District Council of Elliston	Speed limits to be a maximum of 60km/h on all commodity routes. Hauling vehicles to be fitted with yellow revolving flashing lights that can be seen through 360 degrees by oncoming or approaching traffic. Driver to stop and give way to other road users where they would normally have priority to allow the other vehicle to clear the intersection prior to the RAV undertaking a turning manoeuvre. No access to commodity routes where there has been greater than 30mm of rain in any 24 hour period.
District Council of Franklin Harbour	Restricted speed loaded or unloaded to 80km/h on sealed council roads outside town limits. Restricted speed loaded or unloaded to 70km/h on unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. Restricted Access Vehicle (RAV) operators are required to inspect all unsealed routes which have received greater than 15mm of rain in the preceding 24 hours to ensure that restriction information the pavement will not be damaged by the RAV operation.
District Council of Kimba	Restricted speed loaded or unloaded to 80km/h on sealed council roads outside town limits. Restricted speed loaded or unloaded to 70km/h on unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on council-maintained roads within town limits. Council has the right to close any district roads if they are deemed to be unsafe or incurring unreasonable damage.
District Council of Lower Eyre Peninsula	Restricted speed loaded or unloaded to 80km/h on sealed council roads outside town limits. Restricted speed loaded or unloaded to 70km/h on unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. No access to unsealed routes which have received greater than 15mm of rain in the preceding 24 hours.
District Council of Mount Remarkable	Maximum permitted speed of 60km/h on all unsealed council roads. Maximum permitted speed of 25km/h if the unsealed road is signposted for flood ways or narrowing. On unsealed roads, travel is suspended during periods of prolonged rain and up to 1 day for every 5mm of rain within the 24 hour period after the rainfall event. Access may be further restricted or deferred in the event of a significant rainfall event. Contact must be made with the relevant traffic management information sources on such an occasion.
District Council of Tumby Bay	Restricted speed loaded or unloaded to 80km/h on all sealed council roads outside town limits. Restricted speed loaded or unloaded to 70km/h on all unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. Restricted Access Vehicle (RAV) operators are required to inspect all unsealed routes which have received greater than 15mm of rain in the preceding 24 hours to ensure that the pavement will not be damaged by the RAV operation.
District Council Streaky Bay	Restricted speed to 80km/h on sealed council roads outside town limits. Restricted speed loaded or unloaded to 70km/h on unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. No access to unsealed routes which have received greater than 15mm of rain in the preceding 24 hours.
LGA Restriction Information Out of Districts - Far West Coast	Speed limits to be a maximum of 60km/h on all commodity routes. No access to commodity routes where there has been greater than 10mm of rain in any 24 hour period.
Northern Areas Council	All council-maintained commodity routes have a 60km/h speed restriction.
Port Pirie Regional Council	Restricted speed loaded or unloaded to 80km/h on sealed council roads outside town limits. Restricted speed loaded or unloaded to 60km/h on unsealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits.
Southern Mallee District Council	All unsealed council-maintained commodity routes have an 80km/h speed restriction.
The Rural City of Murray Bridge	Restricted speed loaded or unloaded to 60km/h on council roads.
Wakefield Regional Council	All unsealed council-maintained commodity routes have a 70km/h speed restriction.
Wudinna District Council	Restricted speed loaded or unloaded to 70km/h on all unsealed council roads outside town limits. Restricted speed loaded or unloaded to 80km/h on all sealed council roads outside town limits. Restricted speed loaded or unloaded to 40km/h on all council-maintained roads within town limits. Restricted Access Vehicle (RAV) operators are required to inspect all unsealed routes which have received greater than 15mm of rain in the preceding 24 hours to ensure that the pavement will not be damaged by the RAV operation. Operators may be liable for the cost of pavement repairs.

Operators are reminded of ongoing maintenance and other road infrastructure works across South Australia and are advised to refer to the South Australia Government’s Addinsight app and the TrafficSA website to ensure their route is not impacted by works.

Operators should also consult the South Australia Height Clearance Map and Limited Access Locations Information Bulletin located on the Approved areas or routes page of the South Australia Government’s website.

Note: Some routes in the Adelaide Metropolitan Area have height restrictions less than 4.3m.

Traffic advisory services - Click to expand

Prior to commencing any journey, operators should review traffic alerts, road closures, travel delays, and other traffic advisory information for participating jurisdictions.

Table 5 provides details and links to official traffic advisory services for each participating jurisdiction. For more information about a particular service, contact the relevant jurisdiction or department via the contact details listed on the service webpage.

**Table 5:** Traffic advisory services
Jurisdiction	Website	Purpose
New South Wales	Live Traffic NSW	View live information about incidents and changes in New South Wales traffic conditions.
Queensland	QLD Traffic	View live information about incidents and changes in Queensland traffic conditions, including outback road conditions.
South Australia	Outback Road Warnings	Access the latest information about temporary closures, restrictions, and warnings for outback roads north and west of Port Augusta.
South Australia	Traffic SA	View live information about incidents and changes in South Australia traffic conditions. Traffic SA is available as a mobile app. See Addinsight download details on the Traffic SA website.
Victoria	VicTraffic	View live information about incidents and changes in Victoria traffic conditions.

Applying for a permit - Click to expand

Access permit applications are required for heavy vehicles that don’t comply with the conditions set out in a notice and when accessing routes that aren’t covered on an approved network.

The following pages provide useful information and resources for submitting access permit applications:

Do I need a permit?: Information and resources for determining whether a road access permit, or a Notice is required to operate on Australian roads.
Access permit application process: Information, resources, and instructions for submitting a valid access permit application.

Related notices

In this tab, you will find a list of national, state and territory notices related to these Notices.

A related notice may be comparable with these Notices or provide alternatives for operators to find the appropriate notice under which to operate.

Related national notices

Jurisdiction	Notice
National	National Class 2 4.6m high and/or 25m Long Vehicle Carrier Authorisation Notice 2024 (No.1) Authorises the use of Vehicle Carriers from 4.3 to 4.6 metres in height, or from 19 to 25 metres in length, or both, in stated areas or on stated routes, during stated hours of stated days and states the conditions under which these Vehicle Carriers may be used.
National	National Class 2 B-double Authorisation Notice 2024 (No.1) Authorises access for Class 2 heavy vehicles that are B-doubles.
National	National Class 2 Heavy Vehicle 4.6m High Livestock Carrier Authorisation Notice 2024 (No.1) Authorises the use of Livestock Carriers from 4.3 to 4.6 metres in height in stated areas or stated routes, during stated hours of stated days and to state the conditions under which these Livestock Carriers may be used.
National	National Class 2 Road Train Authorisation Notice 2022 (No.3) Provides complying road trains access in New South Wales, Queensland, South Australia and Victoria. The national notice introduces simplified and more nationally consistent conditions for road trains, supporting more seamless cross-border access.

Resources

Supporting information

Tools and calculators

Note: This information is intended to provide general guidance only and does not constitute legal advice. We encourage you to obtain independent advice about your legal obligations. If you have any feedback on the information provided please contact us at info@nhvr.gov.au

Road Train MDL Dimension and Axle Spacing Check Sheet

Road Train MDL Dimension and Axle Spacing Check Sheet (XLSX, 60KB)

Considerations

All of the distances are in metres (m), for example, 1.2m and not 1200mm or 120cm
All masses are in tonnes (t) and General Mass Limits (GML), even if requesting Higher Mass Limits (HML)
- Steer: 6t
- Tandem: 16.5t
- Tri: 20.0t
Distances for axle group length and spacing between axle groups are measured between the axle centres of the extreme axles of each group

Check sheet instructions

If required, open the 'Vehicle Dimensions' tab and enter vehicle length, height and width; This will show compliance with Heavy Vehicle (Mass, Dimension and Loading) National Regulation (MDL) dimensions.
Count the number of axle groups (Note: a single axle is one group) and select tab for that number of axle groups
Enter the number of axles for each axle group in light grey boxes
Enter MDL GML axle/axle group mass (tonnes) for each axle/axle group in white boxes. (Note: steer axle mass is recorded as 6t)
In blue boxes, alternately record axle group length (metres) for each axle group (Note: 0 for a single axle) and distance between separate groups
Scroll across to right and compliance with MDL Schedule 1 tables is indicated as PASS or FAIL

Note: If the result is a FAIL, reducing masses at step 4 or increasing distances in step 5 could provide a PASS result. A PASS result means the given information complies with Road train axle spacing mass limits.

Example: 11 axle A-double (single steer, tandem drive prime mover, triaxle semi, tandem dolly, triaxle trailer) 5 axle groups and 4 spacings between groups. Distances for axle group length and spacing between axle groups are measured between the axle centres of the extreme axles of each group.

Image is of an 11 axle A-double with axle spacing markings below the axle groups to show the spacing between axle groups.

Note: These Notices contain various vehicle safety requirements, which may have been superseded or already applied under Heavy Vehicle National Law (HVNL) or other laws such as the Transport Operations ( Passenger Transport) Standard 2010. If you have any feedback on the information provided, please contact us at info@nhvr.gov.au

Participating jurisdiction heavy vehicle resources

For more information about operating a heavy vehicle in participating jurisdictions, refer to the following sites:

New South Wales: Transport for New South Wales (TfNSW) - Heavy vehicles
Queensland: Department of Transport and Main Roads (TMR) - Heavy vehicles
South Australia: Department for Infrastructure and Transport (DIT) - Heavy vehicles
Victoria: Department of Transport and Planning - Heavy vehicle industry

Changes and updates

Date	Summary	Links to resources and communications
10 February 2024	National Class 3 Heavy Vehicle 4.6m High by Construction Semitrailer Dimension Exemption Notice 2024 (No.1) commenced.	C2024G00105
10 February 2024	New South Wales and Queensland Class 3 4.6m High Loaded Semi-Trailer Dimension Exemption Notice 2024 (No.1) commenced	C2024G00116
15 June 2022	National Class 3 Heavy Vehicle 4.6m High by Construction Semitrailer Dimension Exemption Notice 2022 (No.1) commenced.	C2022G00486
15 June 2022	New South Wales and Queensland Class 3 4.6m High Loaded Semi-Trailer Dimension Exemption Notice 2022 (No.1) commenced.	C2022G00485