Performance Based Brake Testers (PBBT). Round Robin Final Report

摘要

This report documents the results of a series of tests in which several differenttypes of performance-based brake testers (PBBTs) were compare side-by-side (i.e. a round robin test) in their ability to accurately measure brake forces (BFs) and wheel loads (WLs) of commercial vehicles (CVs), and to then predict the vehicle deceleration capability for a 32.2. km/hr on-road stopping test. The PBBTs consisted of five roller dynamometers (RD), two flat plate (FP) testers, and one breakaway torque tester (BTT). A PBBT that can also meet a set of functional specifications could be used for law enforcement by safety inspectors once performance-based criteria are codified. In the test program, specific ratios of BF to WL were imposed on both a 5-axle combination tractor semi-trailer and a two-axle straight truck, in both the fully laden and unladen conditions. In each loading condition, the overall vehicle braking capability was set to achieve a proposed minimum requirement of 0.4g, where g is the acceleration due to gravity.