Heavy Vehicle Size and Weight-Test Procedures for Minimum Safety PerformanceStandards

摘要

The report describes two regulatory scenarios pertaining, respectively, to thebasic resistance to rollover and the obstacle avoidance maneuvering capability of longer and heavier commercial vehicles. At the time of the study, new legislation that could allow the nationwide introduction of vehicle combinations heavier than 36,400 kg (80,000 lbs) and longer than twin, 8.5-meter (28-foot) doubles was under consideration. The primary goal of the scenario developed for regulating roll stability was to provide a reasonable assurance that all vehicles operating under thesystem would have a static rollover threshold exceeding 0.35g. Another goal was to allow for qualifying vehicles on a unit-by-unit basis. Simple screening calculations were developed by which vehicle units that would easily meet the stability criterion could qualify. Tilt table test procedures were developed for vehicles 'too close to call' by the screening methods. The primary goal of the scenario developed to regulate obstacle avoidance capability was to provide a reasonable assurance that all vehicles operating under the system would exhibit rearward amplification less than or equal to 2.0. The test procedure developed solves many of the difficult problems associated with deriving a representative measure of rearward amplification from test data and insuring adequate repeatability of test results.