Concessional Mass Limits in Australia: CML, GML, HML and the 2026 Changes
Australia's heavy vehicle mass limit system has three tiers: General Mass Limits, Concessional Mass Limits, and Higher Mass Limits. In May 2026, the NHVR integrated much of the CML network into an expanded GML framework. This guide explains the history, what changed, and what it means for operators and route planning.
Australia's mass limit system: GML, CML, and HML
Australia's heavy vehicle mass limits are set by the Heavy Vehicle National Law and administered by the NHVR across participating jurisdictions. The system has three main tiers, each reflecting a different level of road assessment and operator obligation.
General Mass Limits (GML) are the baseline. They apply to all compliant heavy vehicles on public roads without any permit or accreditation. GML sets maximum masses per axle group: for example, a single steer axle is limited to 6 tonnes, a single drive axle to 9 tonnes, and a tandem group to 16.5 tonnes under standard GML. These limits apply to the vast majority of Australian roads.
Concessional Mass Limits (CML) were introduced to allow higher axle group masses on roads that had been assessed as capable of carrying them, without requiring the full NHVAS accreditation needed for Higher Mass Limits. CML operated on a defined network, published by the NHVR, and allowed masses above GML on those roads subject to specific axle spacing and vehicle configuration requirements. CML provided a middle ground between the GML default and the HML accreditation pathway.
Higher Mass Limits (HML) allow the highest standard masses, above both GML and CML, on a smaller network of roads assessed as structurally suitable. HML requires NHVAS mass management module accreditation. HML vehicles can carry significantly more mass per axle group than GML vehicles on approved roads, but the HML network is more restricted in geographic coverage.
The May 2026 NHVR notice: CML into expanded GML
In May 2026, the NHVR issued a notice fast-tracking a structural change to the mass limit framework. The change integrated a significant portion of the Concessional Mass Limit network into an expanded General Mass Limit framework. For the roads included in the expansion, the higher masses previously available only under CML conditions are now accessible under the new GML limits without CML-specific approval.
The policy intent behind the change is simplified compliance. The CML system required operators to identify whether each road on their route was a CML road, confirm their vehicle met the CML axle spacing requirements, and ensure the combination was configured correctly for CML access. For the expanded GML network, that verification layer is removed for the included roads, reducing the administrative burden on operators running compliant combinations.
The change also affects the NHVR's network access data, which is the source Truck Me uses. Roads that moved from CML to expanded GML now appear as approved GML roads for compliant vehicles in network access queries, rather than requiring CML-specific conditions to be checked. Operators who have saved routes through roads affected by the change should verify that the updated access status reflects correctly in their planning tools.
Not all CML roads are included
The May 2026 expansion covered a defined subset of the CML network. Roads not included in the expansion may still require CML-specific conditions or a permit. Operators should confirm the access status of specific roads through the NHVR network map or Truck Me before assuming GML access applies.
What the change means for operators
For operators whose routes run through roads included in the GML expansion, the immediate practical effect is reduced paperwork. CML approval processes that previously applied to those roads no longer apply. Vehicles operating within the new GML limits on the expanded network are compliant without CML-specific documentation.
For operators who were not using CML previously, the expansion opens access to higher-mass operations on more roads. Routes that were previously restricted to older GML limits can now carry higher masses on the expanded network roads, provided the vehicle meets the configuration requirements for the new GML limits. This may improve payload efficiency on routes that pass through expanded GML roads.
Operators should review their saved routes and route planning processes following the change. Network access data updated by the NHVR flows into Truck Me's routing engine, so routes calculated after the update will reflect the new access status. However, operators who have locked in routes or permit approvals based on the old CML framework should verify their documentation remains current for any roads not included in the expansion.
- Vehicles on the expanded GML network do not need CML-specific documentation for included roads
- Higher mass access on more roads without NHVAS accreditation for the included network
- Operators should check permit conditions that referenced CML roads specifically
- Roads not included in the expansion retain their previous access requirements
- Route planners should re-verify saved routes through the updated NHVR network data
How Truck Me handles mass limit network data
Truck Me uses NHVR API network data to reflect current access status, including changes from the May 2026 GML expansion.
Network data from the NHVR API
Truck Me uses live NHVR network data to determine which roads are approved for your vehicle class and mass configuration. Changes published by the NHVR flow through to the app.
Vehicle profile with GCM and configuration
Store your vehicle's Gross Combination Mass and configuration in Truck Me. Routes are filtered to roads with appropriate mass limits for your combination.
Access code visibility on the map
Roads are colour-coded green (approved), amber (conditional), and red (restricted) for your vehicle class. Mass limit conditions on amber roads are shown before you commit to the route.
Saved route network change alerts
If the mass limit status of a road on a saved route changes, you receive a push notification. The May 2026 GML expansion affected thousands of road segments.
Dual-route comparison
Truck Me compares your NHVR-approved route against an unrestricted route, showing where the approved path deviates and whether the difference is significant for your operation.
Permit and condition flagging
Conditional roads that require a permit or specific mass configuration are flagged in the route summary. You know what documentation is required before departure.
Frequently asked questions
What changed for mass limits in May 2026?
In May 2026, the NHVR fast-tracked a structural change to Australia's mass limit framework by integrating a large portion of the Concessional Mass Limit (CML) network into an expanded General Mass Limit (GML) network. For operators who were previously accessing roads under CML, this means many of those roads are now accessible under GML without the CML-specific conditions that previously applied. The practical effect is simplified compliance and wider network access at higher mass without the administrative burden of CML approval processes for the affected roads.
What is GML and how does it differ from CML?
General Mass Limits (GML) are the default mass limits that apply to all heavy vehicles on public roads without a permit. They set the maximum mass per axle group and per vehicle combination that any compliant vehicle can carry without additional approval. Concessional Mass Limits (CML) were a category of approved mass limits that sat above GML on a defined network of roads, typically allowing higher axle group masses on roads assessed as capable of carrying them. CML required the vehicle to be operating on approved CML roads and often required specific axle spacing configurations.
Do I still need CML approval after May 2026?
For many roads, no. The May 2026 NHVR notice integrated a significant portion of what was previously a CML-only network into the expanded GML network. If the roads you operate on were included in the expansion, you can access those roads under the new GML limits without CML-specific approval. However, not all CML roads moved into GML. Roads that were not included in the expansion may still require CML or permit conditions. Operators should confirm their specific route status through the NHVR's network access data or the Truck Me map.
What is Higher Mass Limits (HML)?
Higher Mass Limits (HML) allow vehicles to carry mass above GML (and above the old CML levels) on a defined network of roads assessed as suitable for higher loads, typically roads with stronger pavement and structures. HML requires the operator to be accredited under the National Heavy Vehicle Accreditation Scheme (NHVAS) mass management module. HML is the highest standard mass limit tier available without a specific route permit and applies to a smaller network than GML.
How do I find out if a road is approved for my mass?
The NHVR publishes network access data through its API and network maps. Truck Me uses this data to show approved, conditional, and restricted roads on the map for your vehicle class and configuration. You can check any road segment for its access status for your vehicle type. For definitive confirmation of a road's mass limit category, operators can also use the NHVR's online network map directly or contact the NHVR.
Does the GML expansion mean I can carry heavier loads?
The GML expansion means that roads previously accessible only under CML are now accessible under GML, which allows higher masses than the old pre-CML GML limits on those roads. For operators who were already using CML, the practical difference is simplified compliance rather than additional mass allowance, since the mass limits themselves are similar. For operators who were not using CML and were restricted to the lower GML limits, the expansion opens access to higher-mass operations on more roads without needing CML approval.
Related guides
NHVR Mass Limits
GML, CML, and HML explained with axle group limits and what triggers each tier.
Heavy Vehicle Compliance
HVNL obligations for operators and drivers, chain of responsibility, and compliance penalties.
NHVR Access Codes
Approved, conditional, and restricted access codes and what conditions attach to amber roads.
Always routing on current NHVR network data
Truck Me uses live NHVR API data, so mass limit changes like the May 2026 GML expansion are reflected in your routes. Join the waitlist for early access.