Two concerns were raised at the 1995 meeting of the TRB General Issues in Asphalt Technology Committee about the new Superpave® volumetric mix design method. First, although the method includes a mixture analysis system, it is too complicated and time-consuming for use in routine mix design work and a simple, practical test should be substituted for validating hot-mix asphalt (HMA) performance; second, the Superpave volumetric mix design procedure does not define the effects of binder stiffness on mix performance. It essentially relies on limits on the compaction curve to define a good aggregate structure and minimum voids in mineral aggregate to provide durability. Committee members believed that a performance test to complement this procedure would allow the evaluation of the total mix, including the effects of binder. It would also allow the designer to determine how much binder a mix could tolerate before it becomes unstable. Indirectly, this test could aid in producing more durable mixes. The objective of this circular was to identify practical and reliable laboratory tests that could be considered for ranking the rutting potential of HMA paving mixtures. A practical test usually can be performed in less than 24 hours (according to generally accepted industry standards) at a reasonable cost by laboratory personnel with a normal amount of training. This also means that the equipment should be affordable (less than $60,000) and not require elaborate setup. A reliable test must show a reasonable correlation to field performance (i.e., it could be used to establish realistic pass-fail criteria).