Specifications

Brake assessment manual Ver 1.0 Published October 2013 47 (48 pages)
Appendix 6: Rationale for the brake tests in Appendix 5
The Regulation specifies that the applicable vehicle standards are those contained in its
Schedule 2. For vehicles manufactured after 1972, those standards are the Australian
Design Rules (ADRs), and for brake systems, the applicable ADRs are ADR 31 Brake
systems for passenger cars, and ADR 35 Commercial Vehicle Brake Systems. This Manual
is primarily concerned with ADR 31.
Prior to the introduction of ADR 31 in 1977, there was no uniform national standard that
applied to brake systems. Instead, manufacturers largely based the performance and
reliability of brakes on their own specifications or a standard approved by a recognised
standards writing organisation or technical body. The tests specified in Clause 136 to
Schedule 2 in the Regulation that apply to pre-ADR vehicles are intended to check the
roadworthiness of a registered vehicle, and not to determine the effectiveness of a modified
brake system or the brakes in a modified vehicle. This means there are no standards and
tests in the Regulation that can be applied to pre-ADR vehicles to assess their modified
brake systems.
As these vehicles are being modified – as opposed to restored or simply maintained – in a
similar manner and to achieve the same performance outcomes as later ADR vehicles, it is
appropriate that all modified vehicles be subjected to the same tests regardless of their date
of manufacture. This means that the modification should be done, as far as is reasonably
practicable, in accordance with current standards, namely ADR 31/-- using the specified
tests. A review of the tests specified in the different editions and versions of ADR 31/--
showed that the easiest set of tests to do are those in ADR 31/00 and ADR 31/01. The tests
outlined in Appendix 5 are based on these tests.
Most of the tests have been modified to take into account that the tests specified in ADR 31/-
- are intended to verify the effectiveness of a new braking system in a new, mass produced
vehicle model; in contrast, in the majority of cases, the vehicles that are subject to the brake
test schedule are existing, registered vehicles that have previously been proven to comply
with the applicable vehicle standards, and many are being modified with components
sourced from existing vehicles or have otherwise been approved. To allow for this, typically,
both the number of repeats necessary and the test speeds have been reduced. In some
extreme cases, however, a full ADR test will be required.