Oversize Overmass

Oversize and/or Overmass (OSOM) vehicles and loads

The heavy vehicle industry often needs to transport large or heavy objects that are beyond the normal mass and dimension limits. The vehicles that carry out these big moves are commonly referred to as oversize overmass (OSOM) vehicles but more formally the Heavy Vehicle National Law (HVNL) refers to these as Class 1 ‘load-carrying vehicles’.

What is an Oversize and Overmass vehicle

A heavy vehicle is a Class 1 load-carrying vehicle:

• when a vehicle or combination which alone, or together with its load, exceeds prescribed mass or dimension requirements, and
• is carrying, or designed for the purpose of carrying, a large indivisible item.

Examples include a prime mover and extendable trailer or a prime mover and low loader combination.

What is a large indivisible item?

Under the HVNL, a large indivisible item is an item that:

1. cannot be divided without extreme effort, expense, or risk of damage to it; and
2. cannot be carried on any heavy vehicle without contravening a mass or dimension requirement.

Some examples of common large indivisible items include:

• construction or mining equipment like excavators, bulldozers, and other construction equipment that cannot be disassembled without significant effort, expense, or risk of damage.
• wind turbine components such as turbine blades, tower sections, and other components that are designed as single units and cannot be broken down further without compromising their structural integrity.
• prefabricated bridge beams and girders that cannot be divided without affecting their structural strength or causing damage.
• oversized tanks, pressure vessels and alike that are designed and fabricated as single units, making them difficult and expensive to divide.
• modular buildings and large prefabricated structures that cannot be divided without compromising their structural integrity or functionality.
• agricultural machines or implements like harvesters, air seeders, augers and other machinery that cannot be disassembled without significant effort, expense, or risk of damage.

Note: Repurposed freight containers are not freight containers for the purpose of vehicles operating under Class 1 mass or dimension exemptions.

On this page

• How do I get access?
• Pilot and escort vehicles
• Operating conditions applying to Class 1 heavy vehicles
• Loading requirements
• Notices
• Submit my application

How do I get access?

1. Check the notices and national network maps for your journey.
   This will show you all the latest schedules and conditions for your intended route. If your journey is covered by a gazette notice, you won’t need to apply for an OSOM permit. Take me to the notices.
2. Check your third party requirements.
   Notices, permits, and in some cases other laws outside of the HVNL, may require other parties to provide permission for travel. Learn more about third party approvals.
3. Apply for a permit if you cannot operate under a notice.
   To begin your permit application, navigate to NHVR Go. Complete all relevant information, plan your route, and submit your application. I’m ready to begin my application
   Permit applications for travel in all jurisdictions, except Northern Territory and Western Australia, are processed through NHVR Go. Learn more about our application process.
   For travel within the Northern Territory and Western Australia, you need to apply directly to the relevant state or territory road transport authority.

Pilots and escort vehicles

Some oversize movements require a pilot and/or escort. If your movement requires a pilot and/or escort, please review:

• Providing permit copies to pilot and escort vehicle drivers - Rules for heavy vehicle operators when being accompanied by a pilot and/or escort vehicle.
• Pilots and escort training and recognition (PDF, 240KB) - An overview of the pilot and escort requirements in all jurisdictions.
• Driver of pilot vehicles information for Victoria | Transport Victoria - Provides information on training and qualification requirements for pilot vehicle drivers in Victoria. 

All aspects of piloting/escorting are regulated by state and territory road transport authorities, except for Victoria. More information can be found at NHVR Victorian escort services.

Operating conditions applying to Class 1 heavy vehicles

The Heavy Vehicle (Mass, Dimension and Loading) National Regulation (MDL) sets out mandatory conditions that Class 1 heavy vehicles must comply with; these include general conditions and additional conditions relating to load-carrying vehicles.

General conditions

Details about the general conditions are summarised on Schedule 8 - Conditions applying to Class 1 heavy vehicles.

Additional conditions

The key additional conditions that apply to OSOM vehicles include:

Towing a low loader dolly with an unladen low loader

A low loader dolly must not be towed in combination with an unladen low loader unless:

• the combination is not wider than 2.5m; and
• loading or unloading the dolly would be exceptionally difficult because of the nature of the site or because of the short distance to be travelled.

Requirements for carrying multiple items

A load-carrying vehicle can carry more than one large indivisible item, if certain conditions are met. More information can be found at Multiple items on Class 1 load-carrying vehicles.

Loading requirements

To meet the loading requirements, a Class 1 load-carrying vehicles must be loaded:

• in a way that load placement does not make the vehicle unsafe or unstable
• in a way that the load is not likely to fall or be dislodged from the vehicle
• using an appropriate method to restrain the load.

More information can be found at Loading.

Notices - OSOM access

Please note: The table below shows the most common notices used for OSOM vehicles and combinations. For a full list of notices and schemes please see Notices and permit-based schemes.

National notices

State or territory notices

Submit my application

Before you submit your application, check the Do I need a permit? page.

Need help? Contact us for specialist guidance and assistance.

Online application

Post or fax application

Please note: If you apply through post or fax, all correspondence relating to that application will be done through the same channel.

Select application form:

• Oversize Overmass permit application form (PDF, 1.3MB)
• Additional Axle Mass and Spacings attachment (PDF, 290KB)