Braking systems for b-doubles and road trains - Queensland


You must comply with one of the following Australian Design Rules (ADRs) if you manufacture a prime mover used in a B-double or a vehicle used in a road train:

  • second edition ADR 35A
  • third edition ADR 35.

If you operate a prime mover in a B-double that fulfils one of the following conditions, you must also have an anti-lock braking system complying with third edition ADR 64:

  • built after 1989
  • first used in a B-double after 1993
  • is used in a B-double that includes a road tank vehicle carrying dangerous goods.

If you operate or modify a heavy trailer used in a B-double or road train, you must comply with ADR 38.

Australian Design Rule:

  • 35 / 35A specifies the braking requirements on commercial motor vehicles and larger passenger vehicles.
  • 38 specifies requirements for braking under both normal and emergency conditions for trailer brake systems.
  • 64 specifies additional design and construction requirements for hauling vehicles designed to be used in road trains and B-doubles.

Service type

Code of Practice

A code of practice is a set of rules which details how people in a certain industry should behave. A code of practice can be defined as a result of legislation or by industry regulators and bodies.

Administering agency

National Heavy Vehicle Regulator

Contact details

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