South Australia grain trucks get higher mass limits through 2031

The National Heavy Vehicle Regulator has granted South Australia’s grain hauliers higher mass limits for class 3 heavy vehicles carrying grain directly from farm to grain receiver, effective from 30 October 2026 until 31 July 2031. The instrument, the South Australia Class 3 Grain Transport Mass Exemption Notice 2026 (No.3), was published in the Government Notices of the Commonwealth of Australia Gazette of 30 October 2026 under official reference C2026G00710. It revokes and replaces the South Australia Grain Transport Mass Exemption Notice 2026 (No.2).

The notice is made under section 117 of the Heavy Vehicle National Law, which empowers the Regulator to exempt a category of class 1 or 3 heavy vehicles from mass or dimension requirements, and under section 23 of Schedule 1 of that Law. It exempts eligible vehicles from the general mass limits for a single vehicle or combination, for a single axle or axle group, and those relating to axle spacing generally, set out in Schedule 1 of the Heavy Vehicle (Mass, Dimension and Loading) National Regulation. The exemption applies only to the extent that conditional mass limits are given in the notice, the more restrictive limit prevails where two apply, and manufacturer mass limits can never be exceeded.

Which vehicles can use it

The exemption covers class 3 combinations transporting grain directly from a farm to a grain receiver, meaning a place where grain is delivered for measurement, grading and storage before distribution. Permitted configurations include:

• rigid trucks, rigid truck and trailer, and rigid truck combinations
• prime movers towing semitrailers, B-doubles, A-doubles and road trains
• B-triples, B-triples (modular), AB-triples, BA-triples and A-triples
• ABB-quads and BAB-quads

Excluded are combinations with a pig trailer, those fitted with a tri-axle drive configuration, those with an axle group of more than three axles, and Performance Based Standards vehicles.

New mass ceilings

For a vehicle or combination, the maximum mass depends on configuration:

• a complying steer axle vehicle that is neither a B-double nor a road train: 46.2 tonnes
• a Euro VI complying steer axle vehicle of the same class: 46.7 tonnes
• a Euro VI vehicle with a single steer axle: 46.2 tonnes
• a Euro VI twinsteer prime mover towing a tri-axle semitrailer: 50.4 tonnes
• a twinsteer prime mover towing a tri-axle semitrailer: 49.8 tonnes
• any other eligible vehicle: 45.6 tonnes

At axle level, a single steer axle is capped at 6.5 tonnes in most cases, rising to 7.1 tonnes on certain road train hauling units with tyres of at least 375mm section width. A single axle or axle group with dual tyres is limited to 9.0 tonnes; a twinsteer group to 10.0 tonnes without load sharing, 11.0 tonnes with it and 11.5 tonnes for Euro VI twinsteer vehicles on tyres of at least 275mm. Tandem groups with dual tyres are limited to 17.8 tonnes, while tri-axle groups reach 22.0 tonnes without a certified road friendly suspension system and 23.6 tonnes with one.

Accreditation and the harvest window

Operators exceeding 17.0 tonnes on a dual-tyred tandem group, or 21.0 tonnes on a dual-tyred tri-axle group, must hold Alternative Compliance Accreditation (ACA) – Mass, or mass management accreditation granted before 1 August 2026. Travel is approved only during the grain harvest period from October to January.

Routes and access

Vehicles without a certified road friendly suspension system may access all roads except those restricted in the Guide if they are a rigid truck up to 12.5m, a rigid truck and trailer up to 19m or a prime mover and semitrailer up to 19m. Larger combinations must stay on stated networks: the 23m and 26m B-Double Networks (GML), the 36.5m and 53.5m Road Train Networks (GML) and the Commodity Routes – Grain (GML), which are not approved for higher mass limits operation. Vehicles fitted with a certified road friendly suspension system gain access to the higher mass limit networks, from the 19m Network (HML) through the 23m and 26m B-Double (HML) and 30m, 36.5m and 53.5m Road Train (HML) networks to PBS Routes Level 3A and 3B. Road, travel and vehicle conditions imposed under sections 160 to 162 of the Heavy Vehicle National Law continue to apply.

The notice is signed by Jose Arredondo, Manager Network Access Policy at the National Heavy Vehicle Regulator. For growers and carriers, it fixes the payload rules for the harvest now underway and locks them in for five seasons, giving operators certainty to invest in higher-productivity combinations while keeping access tied to certified suspensions and accreditation.

Source: Commonwealth of Australia Gazette, Government Notices, 30 October 2026 (official reference: C2026G00710).