Which heavy vehicles can operate at 20 metres?
Short answer
From 1 August 2026, eligible prime-mover/semitrailer and rigid-truck/trailer combinations can operate at up to 20.0 metres under general access only when every prescribed braking, trailer, dimension, mass and route condition is satisfied.
Plain English
The extra metre is conditional, not automatic. A combination over 19.0 metres and up to 20.0 metres must fit the eligible category, and every heavy trailer in the combination must comply with ADR 38/05 or a later version and have its braking system powered by the towing vehicle.
What this means operationally
Measure the complete combination and verify the actual trailer’s ADR certification and brake actuation. For a prescribed semitrailer whose front articulation point to rear-overhang line exceeds 9.5 metres, verify the wheelbase-dependent dimension limits and ADR 106/00 side-underrun protection. Continue to check mass, width, height, rear overhang, swept path, signs and route restrictions.
Who it applies to
Operators, drivers, fleet engineers, dealers, body builders, trailer manufacturers, loaders and freight customers planning eligible combinations above 19.0 metres and no more than 20.0 metres in an HVNL jurisdiction.
Example
A compliant 19.8 metre prime-mover and semitrailer may use general access only after the operator verifies the trailer’s ADR 38/05-or-later braking, towing-vehicle brake power, all applicable semitrailer dimensions and the route restrictions.
Exceptions and traps
The 20.0 metre general-access pathway does not turn B-doubles, road trains or two-deck car carriers into general-access vehicles. A build date or compliance plate alone is not proof that every condition is met, and a sign, closure, bridge limit or other restriction can still prohibit the trip.
What changed
The current Mass, Dimension and Loading regulation increased the relevant general-access combination length from 19.0 to 20.0 metres on 1 August 2026 and introduced detailed braking and prescribed-semitrailer conditions.
Previous rule
Before 1 August 2026, the relevant combinations were generally limited to 19.0 metres for general access unless another access instrument applied.
Legal foundation
Heavy Vehicle (Mass, Dimension and Loading) National Regulation 2013, Sch 6 ss 3-5; ADR 38/05 or later; ADR 106/00
Sources & primary documents
- www.legislation.qld.gov.au/view/whole/html/inforce/current/sl-2013-0077
- www.nhvr.gov.au/road-access/mass-and-dimension/general-access-vehicle
- www.nhvr.gov.au/road-access/mass-and-dimension/dimension-requirements/length
- www.nhvr.gov.au/document/863
WWTG verification: Queensland legislation, NHVR
Frequently asked questions
Is every 20 metre truck combination now general access?
No. Only an eligible combination meeting every current condition can use the 20 metre pathway.
Which trailer braking standard applies?
Each heavy trailer in a combination over 19 metres and up to 20 metres must comply with ADR 38/05 or a later version and be powered by the towing vehicle.
Does the rule apply only when trailer GTM exceeds 10 tonnes?
No such 10-tonne qualifier should be used for this condition; the current regulation refers to each heavy trailer in the combination.
Is side-underrun protection relevant?
Yes. ADR 106/00 applies to the prescribed semitrailer category identified by the current dimension rule.
Is a permit still required?
Not if the combination fully qualifies for general access and the route has no contrary restriction; otherwise a notice, permit or different vehicle plan may be required.