General Mass Limits (GML) are the basic mass limits that apply to all heavy vehicles. The GML for individual axles and axle groups as well as mass limits for axle spacings of a heavy vehicle. Details about GML are contained in the Heavy Vehicle (Mass, Dimension and Loading ) Regulation.
Vehicles operating at GML can operate on the entire road network, subject to any restrictions imposed by local signage.
The loaded mass of a vehicle must not exceed the manufacturer’s rating, particularly the Gross Vehicle Mass (GVM) for a rigid vehicle or the Gross Combination Mass (GCM) for combinations or Aggregate Trailer Mass (ATM) for trailers. The manufacturer’s mass rating on any component, such as a tow coupling, tyre, wheel or axle, must not be exceeded.
Axle mass requirements
Axle mass
Details relating to axle mass limits are based on limits set out in the MDL Regulation, Schedule 1 Part 2.
- Mass limits for twinsteer prime movers towing tri-axle semitrailers info sheet (PDF, 218KB)
- Mass limits for eligible 2-axle buses under the Heavy Vehicle National Law (PDF, 334KB)
Axle spacing mass limits
Mass limits are impacted by the length of the axle spacing. Figure 1 below shows the measurement points to determine axle spacing, including the:
- distance from the centre-line of single axle to the centre-line of another single axle;
- distance from the centre-line of single axle to the centre-line of the furthest axle in any axle group
- greatest distance between the centre-line of axles in any 2 axle groups.


More information on mass can be found in Table 2 - Axle Spacing Mass Limits General Table in the MDL Regulation, Schedule 1 Part 2.