Heavy Vehicle Brake Safety on Long and Very Steep Roads

Austroads commissioned ARRB Group (ARRB) to conduct a project, the main objective of which was to improve knowledge and understanding of heavy vehicle brake safety on Environment 3 roads (E3 gazetted long steep and very steep) in Queensland. This was achieved through a three-stage project. This document details all three stages in the order they were undertaken. Stage 1 involved a literature review. The topics covered in the literature review reflected the issues relating to heavy vehicle brake safety on long steep and very steep roads. Areas of study included a description of service brakes and auxiliary braking devices, Intelligent transport systems (ITS) pertaining to heavy vehicle braking on slopes and both Australian and international braking regulations. Stage 2 was an analysis of available crash data to examine the magnitude of this issue. Only data from Queensland and New Zealand was able to be analysed as it contained the required information regarding each crash and had an acceptable volume of incidents. Stage 3 involved a vehicle test program where the performance of two articulated heavy vehicle combinations was investigated. Driver behaviour was also of interest, specifically how the various auxiliary braking technologies were understood and used.