National roller brake testing procedure

The NHVR is currently drafting a national set of roller brake testing procedures in partnership with industry and jurisdictions.

This follows concern raised by the heavy vehicle industry that some brake performance tests were delivering inconsistent results due to vehicle design features and test conditions.

The NHVR’s aim is to ensure that all brake performance tests of heavy vehicles are safe, fair and repeatable, enabling assessment of a vehicle's brake system to ensure they can safely and effectively operate on the road network. It also assures us that a vehicle’s braking system complies with the vehicle safety standards.

Transition period

A transition period in NSW is currently in place to allow heavy vehicles that achieve a brake test result greater than 3kN/t, but less than 4.4kN/t, to be given an official warning on first time detection.

During this time, the NHVR and heavy vehicle industry groups have been conducting additional research and trials to determine what factors adversely affect an accurate assessment of the overall braking performance of the heavy vehicle being tested.

The transition period is due to end on 31 January 2018.

Recent Trials

A test program organised by NSW Roads and Maritime Services (RMS), NHVR, Heavy Vehicle Industry Australia (HVIA) and the Australian Trucking Association (ATA) was conducted at NSW RMS Marulan heavy vehicle testing site on 14-15 August 2017. 

A program of 21 trials was conducted with the heavy vehicle combinations either laden or unladen.

The trials included deceleration tests and roller brake tests on up to three roller brake machines. The roller brake machines used were a Maha in-ground, a Nepean in-ground and a Levanta portable.

The objective of the trials was to gain better understanding of how actual heavy vehicle brake performance relates to test results for roller brake machines.  The trials were aimed specifically at the Australian in-service compliance environment where vehicles are tested as presented and without simulated load or tie down. 

Both static and dynamic mass test method results were recorded with a view to identify the best method to ensure compliant brake systems will not be incorrectly defected and to improve safety outcomes by ensuring defective brakes can be identified.

The heavy vehicle roller brake trials have generated a large amount of test data, that is currently being compiled for analysis.

Background

A heavy vehicle’s ability to brake effectively and efficiently is critical to the safe operation of the vehicle on roads. Given the importance of a vehicle’s brakes, regulators, operators, drivers and the community have an interest in ensuring rigorous assurance processes are in place to verify brake performance.

Taking into account the location, time and safety limitations of the road side or workshop, the NHVR and industry utilise various brake testing methods that provide an indication of brake performance. This includes decelerometer testing at lower speeds, and skid plate testing or roller brake testing using test equipment. Collectively these test methods are referred to as in-service brake tests.

Roller brake testing, like all in-service brake tests, is intended as a screening tool to verify that a vehicle’s braking system is functioning and provide information that highlights potential issues relating to non-compliances and/or system performance. This information can then be used to determine if repair is required and/or if inspection of specific brake components is needed.