Road train trailer requirements

Road train vehicle and trailer components, such as brakes, tow couplings and drawbars, experience significantly higher loads and stresses than other combinations. To ensure road trains operate safely, the Heavy Vehicle National Law (HVNL) and Australian Design Rules (ADRs) apply specific requirements to vehicle components used in road trains. Operators and other parties in the Chain of Responsibility (CoR) must ensure that vehicles used in road train combinations comply with these safety-critical requirements.

A simple way for operators to check whether the trailer is specified for use in a road train is to check the manufacturer’s plate. This will show whether the vehicle has been built to meet the specific requirements for use in a road train combination. Operators can also check whether there is a modification plate fitted showing VSB 6 Code S11. If the manufacturer’s plate does not indicate suitability for use in a road train combination and there is no modification plate showing VSB 6 Code S11, a more detailed check will be required to confirm compliance.

The information in the table below will assist operators and other parties in the CoR to perform this detailed check. It outlines road train trailer requirements and provides references to where more detailed information may be found.

Note: Road trains operating under the Performance Based Standards (PBS) scheme must comply with the conditions of their Vehicle Approval (VA).

For more information, call 13 NHVR (13 64 87) or email info@nhvr.gov.au.

Requirement

Detail

Reference

Identification plates
  • Identification plate or manufacturer’s plate showing the vehicle is a road train trailer (if the identification plate is on the vehicle).
  • Modification plate – VSB 6 Code S11, indicating modification to ‘road train’ specifications.

 

Warning signs
  • Combinations longer than 30m must display a ‘road train’ warning sign at the front and rear.
  • Combinations longer than 22m but not longer than 30m must display a ‘long vehicle’ warning sign at the rear.

The signs must be fitted so:

  1. the lower edge of the warning sign is at least 500mm above ground level; and
  2. the upper edge of the warning sign is no more than 1.8m above ground level.

For rear marker plate requirements, see VSB 12 Rear Marker Plates.

Length
  • Must not exceed 12.3m when measured from the front articulation point to the rear of the trailer.
  • ADR 43/04
  • Schedule 6 section 4 Heavy Vehicle (Mass, Dimension and Loading) National Regulation (MDL Regulation)

Drawbar
  • The drawbar length must not be less than 3.0m but must not exceed 5.0m.

Brakes
  • Must meet second or third edition ADR 38 or ADR 38/00. (38/00 is applicable to trailers manufactured on or after 1 July 1988).

Brakes (anti-lock braking system)
  • Regardless of build date, the trailer must be fitted with an anti-lock braking system if is a road tank vehicle and is carrying dangerous goods.

King pin rating
  • Fifth wheel kingpins must comply with the requirements of Australian Standard 2175-1990 Articulated Vehicles ‑ Kingpins and have a D-value of not less than 162kN (16.5t).
  • ADR 63

Fifth wheel rating
  • Fifth wheel assemblies must comply with the requirements of Australian Standard 1773-1990 Articulated Vehicles ‑ Fifth Wheel Assemblies and have a D-value of not less than 162kN (16.5t).
  • ADR 63

Auto pin coupling location
  • The vertical axis of the coupling pivot must be not more than 300mm forward from the rearmost projection of the trailer (63.5.1.3).
  • The tow coupling overhang must not exceed:
  • in the case of a trailer other than a semitrailer, 30% of the distance from the centre of the front axle group to the centre of the rear axle group; or
  • in the case of a semitrailer, 30% of the distance from the point of articulation to the centre of the rear axle group.
  • ADR 63

Auto pin coupling rating
  • Tow coupling assemblies must comply with Australian Standard 2213-1984 50 mm Pin-type Couplings and Drawbar Eyes for Trailers and must have a ‘D-value’ of not less than 186kN (19.0t).
  • ADR 63

Coupling height
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