This synthesis will be of special interest and usefulness to construction engineers, materials technologists, and others concerned with control and assurance of quality in highway construction. Detailed information is presented on quality assurance philosophies, programs, practices, and procedures. Administrators, engineers, and researchers are faced continually with many highway problems on which much information already exists either in documented form or in terms of undocumented experience and practice. Unfortunately, this information often is fragmented, scattered, and unevaluated. As a consequence, full information often is fragmented, scattered, and unevaluated. As a consequence, full information on what has been learned about a problem frequently is not assembled in seeking a solution. Costly research findings may go unused, valuable experience may be overlooked, and due consideration may not be given to recommended practices for solving or alleviating the problem. In an effort to correct this situation, a continuing NCHRP project, carried out by the Transportation Research Board as the research agency, has the objective of synthesizing and reporting on common highway problems. Syntheses from this endeavor consitute an NCHRP report series that collects and assembles the various forms of information into single concise documents pertaining to specific highway problems or sets of closely related problems. Many factors influence the performance of highways and bridges. This report of the Transportation Research Board reviews these factors and outlines the major components of quality assurance systems used by state highway agencies to ensure compliance with specifications. A number of states have reported favorable experience in basing their testing and inspection procedures on end- result or performance type specifications. Use of statistical probabilities in quality control and assurance programs is also discussed in this report. To develop this synthesis in a comprehensive manner and to ensure inclusion of significant knowledge, the Board analyzed available information assembled from numerous sources, including a large number of state highway and transportation departments. A topic panel of experts in the subject area was established to guide the researchers in organizing and evaluating the collected data, and to review the final synthesis report. This synthesis is an immediately useful document that records practices that were acceptable within the limitations of the knowledge available at the time of its preparation. As the processes of advancement continue, new knowledge can be expected to be added to that now at hand.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3491