AN OVERVIEW OF PERFORMANCE MEASURES FOR HEAVY COMMERCIAL VEHICLES IN NORTH AMERICA.

In recent studies, it has become apparent that a set of safety-related performance measures for heavy vehicles can be useful in the design process as well as in the more conventional realm of screening heavy vehicles by regulation. In Canada, these regulations control, separately, the combined trailer length and overall vehicle length, total vehicle weight, maximum axle-load, multiple-axle group spacing, and the characteristics of a few selected components of new vehicles (e.g. service and emergency air and/or hydraulic brake systems). None of the existing regulations has been applied for quantifying the dynamic properties of individual vehicles, either newly designed or already in service; instead they have been used to qualify classes or groupings of vehicles. The objective of this paper is to present an overview of the efforts made in North America to develop a set of safety-related performance measures and promote their use for determining and controlling the dynamic quality of heavy vehicles on an individual basis from both the design and regulatory standpoints.