This synthesis documents the performance tests used in conjunction with volumetric properties for mixtures. Performance tests are intended to extend service life by guiding material selection (i.e., asphalt binder and aggregate) and proportions (i.e., asphalt content and gradations). The synthesis provides examples of engineering tools used in the development and implementation of performance specifications for asphalt mixtures, examples of the contents of performance-based specifications (PBS) currently used or in development, information on test program implementation and research efforts related to PBS for asphalt mixtures, and the reported benefits and challenges with implementing PBS. Information for this report was acquired through a literature search, a survey of the use of performance specifications for asphalt mixtures, and seven case examples from six state departments of transportation, and the city of Edmonton, Alberta, Canada.