Truck and trailer rules in New South Wales: licence classes, trailer brakes and size limits

This page reports what the official source says. It is not legal advice: ask the office named here. The sources are three Transport for NSW pages on nsw.gov.au and four pages of the National Heavy Vehicle Regulator (NHVR), all read on October 10, 2026. The NHVR pages cover the Heavy Vehicle National Law limits that apply to heavy vehicles. Federal background and the other places are on the parent page, trucks and trailers for tree work, and the Australian licence classes by weight are also on driving the chip truck.

At a glance

Item	What the sources say
Heavy vehicle classes	Five: LR, MR, HR, HC and MC
Light Rigid	Trucks up to 8 tonnes GVM; a towed trailer not over 9 tonnes GVM
Medium Rigid	Trucks with a GVM over 8 tonnes and 2 axles
Heavy Rigid	Trucks with a GVM over 8 tonnes and 3 or more axles
Heavy Combination	Articulated vehicles with 3 or more axles, or any towed trailer with a GVM over 9 tonnes
Trailer brakes	None required up to 750 kg gross trailer mass; both wheels of one axle at 751 to 2,000 kg; all wheels at 2,001 to 4,500 kg
Safety chains	One under 2,500 kg loaded; two over 2,500 kg loaded
Height, width	4.3 metres high and 2.5 metres wide for a heavy vehicle, with listed exceptions
Length	12.5 metres for a heavy vehicle not named in the length list; combinations 19 or 20 metres

Licence classes

Transport for NSW says there are five heavy vehicle licence classes: Light Rigid (LR), Medium Rigid (MR), Heavy Rigid (HR), Heavy Combination (HC) and Multi Combination (MC). Its page describes each by gross vehicle mass (GVM) and axles. LR covers small trucks with a GVM up to 8 tonnes, with any towed trailer not over 9 tonnes GVM, and buses that seat more than 12 adults. MR covers trucks and buses with a GVM over 8 tonnes and two axles, and HR covers those with three or more axles. HC covers articulated vehicles with three or more axles, heavy rigid and trailer combinations with three or more axles, and any towed trailer with a GVM over 9 tonnes. MC covers B-doubles, prime mover and low loader combinations, and road trains.

The same page sets the steps to a licence. An applicant must pass the Heavy Vehicle Knowledge Test, an eyesight test, and either a Heavy Vehicle Competency Based Assessment with a registered training organisation or a heavy vehicle driving test with a Service NSW testing officer where the assessment is not available. For LR and MR the page asks for a class C licence or equivalent held for 1 year or more, for HR 2 years or more, for HC an MR or HR licence held for 1 year or more, and for MC an HR or HC licence held for at least 1 year, plus a medical assessment. It says a higher class also lets the holder drive vehicles of the lighter classes, not motorcycles.

Trailer brakes, couplings and chains

The Transport for NSW towing page sets the minimum braking system by gross trailer mass (GTM). Up to 750 kg needs no brakes, and brakes that are fitted must comply. From 751 to 2,000 kg the page asks for an efficient braking system on both wheels of at least one axle. From 2,001 to 4,500 kg it asks for efficient brakes on all wheels. Each trailer with a GTM over 2.0 tonnes must have an automatic breakaway system, and brakes must be operable from the driver's seat. Couplings must be strong enough for a fully loaded trailer and have a positive locking mechanism that can be released at any angle. Safety chains must comply with Australian Standards: at least one chain under 2,500 kg when loaded and two over 2,500 kg, as short as practicable, connected to the towing vehicle and crossed over when two are fitted. A vehicle over 4.5 tonnes GVM, or a combination over 4.5 tonnes gross combination mass, towing a single trailer must not exceed 100 km/h whatever the signposted limit. The page limits a driver to one trailer at a time. The NHVR length page adds that a combination counts as limited to 19 metres when it includes a heavy trailer that has no braking system meeting ADR 38/05 or a later version and does not draw braking power from the towing vehicle; otherwise the limit is 20 metres. This applies to a combination other than a B-double, road train or vehicle carrier.

Size and mass limits

Limit	Figure as printed	Source
Height	4.3 metres, with 4.6 metres for livestock carriers, vehicle carriers with two decks and specified semitrailers	NHVR
Width	2.5 metres; 2.55 metres for new rigid trucks and prime movers fitted with listed safety features, not trailers or buses	NHVR
Length, another vehicle	12.5 metres	NHVR
Length, combination	19 metres, or 20 metres where the trailer brake and other conditions are met	NHVR
Length, car and trailer	19 metres including the load	Transport for NSW
Load width on a trailer	150 mm past the trailer width, or 2.5 metres overall, whichever is less	Transport for NSW
Rear projection	Red flag at least 300 mm square past 1.2 metres behind the trailer	Transport for NSW
Warning triangles	Three, for a vehicle or vehicle and trailer over 12 tonnes GVM	Transport for NSW

The NHVR length and general mass pages say they include amendments to the Heavy Vehicle National Law and Regulations that commenced on August 1, 2026. The Transport for NSW towing page, read on the same date, prints 19 metres for a vehicle and trailer, so both figures are given as the pages print them. The NHVR general mass limits page says the loaded mass of a vehicle may not exceed the maker's rating, and gives 43.5 t for a vehicle not named in its table that is neither a B-double nor a road train, 6.0 t for a steer axle on another motor vehicle, and 15 t where two axles outside a group are less than 2.5 metres apart. It says the general mass limits apply unless the vehicle operates under an exception, an exemption by notice or permit, or a Performance Based Standards approval. The Transport for NSW restrictions page says a driver must not pass a bridge or gross load limit sign if the combined gross mass is above the figure shown. For a no trucks sign without detail it counts a truck as a GVM over 4.5 tonnes.