This report contains guidelines and recommendations for managing and designing for friction on highway pavements. The contents of this report will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements.

A study of the sand-patch and outflow meter methods of pavement surface texture measurement was completed. Included in this study were repeatability testing and testing to determine the degree to which pavement surface texture, as measured by these procedures, correlates with pavement coefficient of friction, skid number, and skid number speed gradient. Test locations were selected on open-graded and dense-graded asphalt concrete, chip-sealed and fog-sealed asphalt concrete, and new, polished, and grooved portland cement concrete (PCC) pavements. The results of the testing indicated that the repeatability of the sand patch test procedures studied was poor to fair and that the outflow meter test results were independent of water temperature. A general trend toward higher skid numbers and coefficients of friction was evident with increasing texture depth, as measured with both the modified sand patch and the outflow meter procedures. However, neither relationship was considered definitive enough to use as a basis for a minimum texture depth construction specification requirement for pavement surfaces. Also, neither method provided a definitive measure of skid number speed gradient.

A comprehensive, state-of-the-art guide to pavement design and materials With innovations ranging from the advent of SuperpaveTM, the data generated by the Long Term Pavement Performance (LTPP) project, to the recent release of the Mechanistic-Empirical pavement design guide developed under NCHRP Study 1-37A, the field of pavement engineering is experiencing significant development. Pavement Design and Materials is a practical reference for both students and practicing engineers that explores all the aspects of pavement engineering, including materials, analysis, design, evaluation, and economic analysis. Historically, numerous techniques have been applied by a multitude of jurisdictions dealing with roadway pavements. This book focuses on the best-established, currently applicable techniques available. Pavement Design and Materials offers complete coverage of: The characterization of traffic input The characterization of pavement bases/subgrades and aggregates Asphalt binder and asphalt concrete characterization Portland cement and concrete characterization Analysis of flexible and rigid pavements Pavement evaluation Environmental effects on pavements The design of flexible and rigid pavements Pavement rehabilitation Economic analysis of alternative pavement designs The coverage is accompanied by suggestions for software for implementing various analytical techniques described in these chapters. These tools are easily accessible through the book’s companion Web site, which is constantly updated to ensure that the reader finds the most up-to-date software available.

This synthesis report will be of interest to pavement design, construction, management, and research engineers, highway safety officials, and others concerned with pavement friction characteristics. It describes the current state of the practice and discusses the methods used for evaluating wet pavement friction characteristics of new and restored pavements. This synthesis reviews models used for measuring and evaluating friction and texture, causes for friction changes over time, and aggregate and mix design to provide adequate friction. Also presented are construction and surface restoration practices for providing good pavement surface characteristics. In addition, considerations of noise and ride quality are discussed when compromise may be required.